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U.S.  pEPAftTMfiNT  OF  AGRICULTURE, 

FOREST  SERVICE  — BULLETIN  80. 

HENRY    S.   GRAVES,   Forester.,   , 


THE  COMMERCIAL  HICKORIES. 


BY 


ANTON  T.  BOTSEN,  FOREST  ASSISTANT, 


J.  A.  NEW  LIN,  ENGINEER  IN  TIMBER  TESTS. 


uu 
OCT 


Uiiiverbity  of  Calif* 


WASH  I  N(r  TON  : 

GOVERNMENT     I'UINTING     OFFICE 

1910. 


q.T  Agriculture. 


PLATE  I. 


A  GROUP  OF  HICKORIES  IN  PUTNAM  COUNTY,  TENN.;  PIGNUT  IN  THE  CENTER,  SHAG- 
BARKS  ON  EITHER  SIDE. 


Issued  October  27,  1910. 

U.  S.  DEPARTMENT  OF  AGRICULTURE, 

FOREST   SERVICE  — BULLETIN   80. 

HENRY    S.   GRAVES,    Forester. 


THE  COMMERCIAL  HICKORIES. 


BY 


ANTON  T.  BOISEN,  FOREST  ASSISTANT, 


AND 


J.  A.  NEWLIN,  ENGINEER  IN  TIMBER  TESTS. 


QCT29  1914 

Division  of  Forestry 
University  of  California 


WASHINGTON: 

GOVERNMENT    PRINTING    OFFICE. 
1910. 


LETTER  OF  TRANSMITTAL 


U.  S.  DEPARTMENT  OF  AGRICULTURE, 

FOREST  SERVICE, 
Washington,  D.  C.,  June  4,  1910. 

SIR:  I  have  the  honor  to  transmit  herewith  a  manuscript  entitled 
"Commercial  Hickories,"  by  Anton  T.  Boisen,  forest  assistant,  and 
J.  A.  Newlin,  engineer  in  timber  tests,  and  to  recommend  its  publica- 
tion as  Bulletin  80  of  the  Forest  Service. 
Very  respectfully, 

HENRY  S.  GRAVES,  Forester. 
Hon.  JAMES  WILSON, 

Secretary  of  Agriculture. 
2 


CONTENTS. 


Page. 

Economic  importance  of  the  hickories 7 

The  annual  consumption 7 

Industries  that  use  hickory 7 

Exports 9 

The  hickory  supply 9 

Present  stand 9 

Ownership  of  land 10 

Lumbering 10 

Stumpage  prices '. 11 

Log  rules 11 

Waste 12 

The  tree  and  its  forms 13 

The  pecan  hickories 16 

Pecan 16 

Water  hickory 16 

Nutmeg  hickory 17 

Bitternut 17 

The  true  hickories 18 

Shagbark « 18 

Big  shellbark 19 

Pignut : 20 

Mockernut 21 

Range  and  distribution 22 

Soil  and  moisture  requirements 25 

Tolerance 26 

Reproduction 26 

Growth ! 29 

Length  of  life 32 

Susceptibility  to  injuries 32 

Volume  and  yield 33 

Volume 33 

Yield 40 

The  wood  and  its  mechanical  properties 41 

Hickory  tests 42 

Description  of  material 42 

Care  of  material 44 

Methods  of  test 44 

Hickory  wood  as  compared  with  others . 45 

Factors  that  affect  strength 46 

Moisture 46 

Weight 47 

Rate  of  growth 48 

Heartwood  and  sapwood 50 

3 


477596 


4  CONTENTS. 

The  wood  and  its  mechanical  properties— Continued. 

Factors  that  affect  strength — Continued.  Page. 

Position  in  the  tree 50 

Age 52 

Soil  and  situation 52 

Geographic  location 52 

Species 55 

Defects 57 

Outlook  for  future  supply 57 

Methods  of  perpetuating  the  supply 58 

Economic  means 59 

Silvicultural  means 60 

Summary 62 


LLUSTRATIONS. 


PLATES. 

Page. 

PLATE  I.  A  group  of  hickories  in  Putnam  County,  Tenn Frontispiece. 

II.  Fig.  1. — Spoke  bolts  cut  from  pignut  hickory.     Fig.  2. — Waste  in 

hickory  bolts  cut  for  spokes 16 

III.  Fig.  1.— Taproot  of  bitternut.     Fig.  2.— Root  sucker  of  hickory 16 

IV.  Fig.   1. — A  group  of  stump  sprouts  of  pignut.     Fig.   2. — Hickory 

sprouts  coming  up  from  the  roots 32 

V.  A  plantation  of  big  shellbark  27  years  old 64 

VI.  Fig.  1. — Reproduction  of  hickory  in  a  field.     Fig.  2. — A  young  stand 

of  hickory  after  cutting 64 

TEXT   FIGURES. 

FIG.  1.  Pecan  (Hicoria  pecan} 14 

2.  Water  hickory  (Hicoria  aquatica) 15 

3.  Nutmeg  hickory  (Hicoria  myristicseformis) 16 

4.  Bitternut  (Hicoria  minima) 17 

5.  Shagbark  (Hicoria  ovata) 18 

6.  Big  shellbark  (Hicoria  ladniosa) 19 

7.  Pignut  (Hicoria  glabra) 20 

8.  Small  pignut  (Hicoria  odorata) 21 

9.  Mockernut  (Hicoria  alba) 22 

10.  Ranges  of  the  pecan  hickories 23 

11.  Ranges  of  the  true  hickories 24 

12.  Strength  and  work  as  affected  by  specific  gravity 47 

13.  Spoke  test  chart,  showing  relation  between  resilience  factor  and  weight.  48 

14.  Strength  and  work  as  affected  by  rate  of  growth 49 

15.  Strength,  work,  and  specific  gravity  as  affected  by  position  in  the  tree. .  51 

16.  Strength,   work,   and  specific  gravity  as  affected   by  height  above 

ground 53 

17.  Relative  values  of  the  various  species  of  hickory 56 

5 


!  nxi  ion  of  Forestry 

THE  COMMERCIAL 


ECONOMIC  IMPORTANCE  OF  THE  HICKORIES. 

Of  American  hardwoods  none  would  be  more  difficult  to  replace 
than  hickory  in  case  of  a  shortage  in  supply.  It  is  not  used  in  such 
quantity  as  white  oak,  or  yellow  poplar,  or  maple,  but  it  is  used  for  a 
number  of  special  purposes  for  which  it  alone  is  satisfactory.  The 
wood  of  the  hickory  is  not  remarkable  for  beauty  of  color  or  of  grain, 
it  shrinks  badly  in  drying,  it  is  not  durable  in  contact  with  the  ground, 
and  it  is  very  liable  to  attack  by  insects ;  on  the  other  hand  it  is  heavy, 
hard,  strong,  stiff,  and  very  tough.  No  other  commercial  wood, 
native  or  foreign,  combines  these  properties  to  so  great  a  degree. 
The  hickory  spoke  and  rim  and  the  hickory  shaft  have  made  possible 
the  American  type  of  spring  vehicle  with  its  superior  lightness  and 
strength ;  the  hickory  handle  has  helped  greatly  to  make  the  American 
ax  known  all  over  the  world. 

The  Forest  Service  has  cooperated  with  the  National  Hickory 
Association,  an  organization  of  the  users  of  hickory  who  have  foreseen 
a  coming  shortage  in  the  supply,  and  who  have  united  to  help  prevent 
it,  to  study  the  different  species,  and  to  suggest  means  to  produce  and 
maintain  the  necessary  supply. 

THE    ANNUAL   CONSUMPTION. 

There  are  no  accurate  figures  of  the  annual  cut  of  hickory.  The 
census  returns  for  1908  show  a  cut  of  about  200,000,000  board  feet. 
This  is  intended  to  include,  however,  only  the  material  actually  cut 
and  sold  as  lumber,  while  much  of  the  hickory  cut  is  not  lumber.  In 
1908  an  additional  cut,  equivalent  to  about  135,000,000  board  feet, 
was  worked  up  directly  into  other  products,  such  as  spoke  billets, 
handle  blanks,  and  rim  strips,  difficult  to  reckon  in  board  feet.  This 
gives  a  total  consumption,  excluding  fuel,  of  about  335,000,000  board 
feet,  allowing  for  all  necessary  waste.  If,  however,  the  unnecessary 
waste,  both  in  the  woods  and  at  the  mill,  were  included,  the  total 
amount  of  hickory  consumed  would  probably  be  not  less  than 
450,000,000  feet. 

INDUSTRIES    THAT    USE    HICKORY. 

The  vehicle  industry  uses  more  hickory  than  any  other,  is  most 
dependent  upon  it,  and  takes  about  65  per  cent  of  the  total  cut.  In 
America  spokes,  rims,  poles,  shafts,  singletrees,  doubletrees,  spring 

7 


8  THE   COMMERCIAL  HICKORIES. 

bars,  and  axle  caps  of  spring  vehicles  ave  all  made  of  hickory;  and 
more  than  one-half  is  used  for  spokes.  In  Europe  oak,  ash,  and 
acacia  are  also  used,  but  they  are  admittedly  inferior,  and  probably 
could  not  be  substituted  for  hickory  in  American  vehicles  without  a 
radical  alteration  of  design  and  a  serious  loss  of  lightness  and  strength, 
for  which  the  American  types  are  celebrated.  About  1  per  cent  of  the 
annual  cut  of  hickory  is  used  in  the  manufacture  of  automobile  spokes 
and  wheel  rims. 

In  the  manufacture  of  heavy  wagons  about  9  per  cent  of  the  total 
output  of  hickory  is  used  mainly  for  axles,  but  also  for  neck  yokes, 
single  and  double  trees,  brake  bars,  and  crossbars.  Sometimes  it 
replaces  oak  for  the  spokes,  although  it  does  not  last  so  long  under 
the  trying  weather  conditions  to  which  wagons  are  so  often  exposed. 

The  tool-handle  industry  annually  uses  about  80,000  cords,  or  10 
per  cent  of  the  total  cut,  of  hickory  for  ax,  pick,  sledge,  hatchet,  and 
other  handles  which  require  toughness  and  strength.  Other  woods 
are  used  for  handles,  notably  hard  maple  and  white  oak,  but  their  use 
is  limited  and  local.  The  agricultural-implement  business  uses  about 
8  per  cent  of  the  total  cut  of  hickory  for  singletrees,  doubletrees,  axles, 
crossbars,  mower  pitmans,  eveners,  neck  yokes,  spokes,  and  rims. 
The  quality  demanded  is  much  the  same  as  in  heavy  wagons,  and  oak 
could,  in  many  cases,  be  used  just  as  well. 

Oil  wells  use  about  2  per  cent  of  the  hickory  output  for  sucker  rods, 
which  must  be  clear  of  defects,  straight-grained,  and  from  18  to  35 
feet  long.  Hickory  rods,  which  are  superior  to  others  in  strength  and 
toughness,  were  at  one  time  used  almost  exclusively,  but  three-fourths 
of  the  rods  now  in  use  are  of  iron  and  the  proportion  must  increase. 
Wooden  rods  have  the  very  important  advantage  over  iron  that  they 
will  float.  This  advantage  is  especially  important  in  deep  wells  where 
a  long  string  of  iron  rods  is  excessively  heavy.  Material  suitable  for 
sucker  rods  is  scarce,  however,  and  wooden  rods  cost  twice  as  much  as 
iron. 

These  industries  together  consume  about  95  per  cent  of  the  total 
cut  of  hickory.  The  other  5  per  cent  is  used  for  many  special  prod- 
ucts, such  as  picker  sticks  in  cotton  and  silk  mills,  skewers,  golf 
sticks,  whipstocks,  ladder  rungs,  dowel  pins,  belaying  pins,  wooden 
screws,  rustic  furniture,  hames,  gymnastic  bars,  scythe  snaths,  and 
quoins. 

Hickory  is  the  best  American  fuel  wood  and  costs  about  25  per 
cent  more  than  any  other.  It  is  probable  that  the  greater  part  of  all 
the  hickory  cut  is  used  for  fuel,  and  this  portion  may  amount  to 
1,000,000  cords.  Not  a  little  of  this,  even  to-day,  is  material  of  the 
best  quality,  which  should  be  saved  for  the  spoke  and  handle  maker. 
In  the  past  tremendous  quantities  of  the  finest  hickory  have  been 
burned. 


THE   HICKOKY  SUPPLY.  9 

The  use  of  hickory  saplings  for  hoops  has  in  the  past  been  very 
important,  but  is  now  on  the  decline.  The  hickory  barrel  hoop  is 
recognized  as  the  best  wooden  hoop,  but  it  is  more  expensive  because 
it  has  to  be  made  by  hand,  and  is,  therefore,  giving  way  to  the  patent 
elm  hoop  and  to  iron  and  wire.  The  prices  of  hickory  hoops  have 
fallen  20  per  cent  during  the  past  ten  years  until  7-foot  hoop  poles 
bring  only  $5  per  thousand,  cut  and  delivered,  and  there  is  now  little 
profit  in  them.  This  is  really  fortunate,  from  the  point  of  view  of 
prolonging  the  hickory  supply,  because  hoop  poles  require  straight, 
clean  saplings  from  1  to  2  inches  in  diameter  and  from  10  to  15  feet 
high ;  this  means  the  destruction  of  the  most  promising  young  growth 
and  the  leaving  of  scrubby  and  knotty  specimens  as  the  basis  of  the 
future  crop,  and  has,  in  fact,  secured  the  survival  of  the  unfit. 


EXPORTS. 


A  great  deal  of  American  hickory  is  used  in  the  vehicle  industry 
abroad.  It  is  exported  chiefly  in  the  form  of  bent  rims,  spokes,  and 
shafts,  but  a  great  many  finished  wheels  and  logs  are  also  sent. 
About  5  or  10  per  cent  of  the  annual  output  is  used  in  this  way.  In 
addition,  large  quantities  of  hickory,  both  in  finished  and  unfinished 
form,  are  sent  to  Canada.  About  40  per  cent  of  the  total  output  for 
tool  handles  is  shipped  abroad,  mainly  to  Germany,  to  South  Africa, 
and  to  Australia. 

THE  HICKORY  SUPPLY. 
PRESENT    STAND. 

Hickory  once  grew  in  commercial  quantities  from  Connecticut, 
New  York,  and  southern  Michigan  south  to  Florida  and  west  to 
Illinois,  Missouri,  Oklahoma,  and  eastern  Texas.  In  this  region  it 
formed,  perhaps,  one-fortieth  of  the  total  hardwood  stand.  Measure- 
ments of  2,000  acres  in  the  Southern  Appalachians,  for  instance, 
showed  that  it  formed  5.1  per  cent  of  the  trees  over  10  inches  in 
diameter.  The  percentage  was  greatest  in  the  Ohio  and  in  the  lower 
Mississippi  valleys. 

The  original  supply  is  now  approaching  exhaustion.  East  of  the 
Alleghenies  and  north  of  the  Potomac  it  has  disappeared  almost 
entirely.  West  of  the  Alleghenies  and  north  of  the  Ohio  only  a  few  scat- 
tered remnants  are  left,  and  the  bulk  of  the  supply  lies  south  of  the  Ohio 
River.  Most  of  the  northern  manufacturers  get  their  supplies  from 
the  South;  all  of  the  larger  operations  are  there  and  competition  is 
very  keen.  The  whole  hickory-producing  territory  has  been  covered 
by  the  timber  buyers,  and  already  some  of  the  larger  companies  are 
working  over  their  old  cuttings,  taking  material  which  had  been 
rejected  ten  or  fifteen  years  ago.  In  only  a  few  years,  probably  not 
more  than  ten,  the  conditions  of  to-day  in  southern  Indiana  and  Ohio 

51762°— Bull.  80—10 2 


10  THE  COMMERCIAL  HICKORIES. 

will  be  duplicated  in  the  South.  The  large  timber  will  be  scattered 
and  hard  to  get  and  the  second  growth  will  become  the  main  source 
of  supply. 

OWNERSHIP    OF    LAND. 

In  the  South,  as  well  as  in  the  North,  hickory,  like  oak,  ash,  and 
tulip  with  which  it  is  generally  associated,  is  owned  mainly  in  small 
holdings.  It  grows  best  on  fertile  soils  in  a  strictly  temperate  climate, 
and  is  most  prominent  in  the  agricultural  regions  of  Ohio,  Indiana, 
western  Kentucky,  and  Tennessee.  Throughout  this  region  the  for- 
ests have  now,  for  the  most  part,  been  cleared  away  to  make  room 
for  agriculture.  Hickory  is, 'and  probably  will  continue  to  be,  a  tree 
of  the  farmer's  woodlot,  though  there  are  a  few  large  holdings  in  the 
river  bottoms  of  the  lower  Mississippi  Valley  and  in  the  Southern 
Appalachians.  In  all  of  these,  however,  the  hickory  grows  in  mix- 
ture with  other  species  and  usually  occupies  a  subordinate  position 
in  the  stand.  None  of  the  larger  holdings  and,  in  fact,  few  of  the 
smaller  ones  are  valuable  chiefly  for  the  hickory  which  they  contain. 
Because  of  this  hickory  users  have  found  it  impracticable  to  buy  up 
and  hold  timber  land  for  the  production  of  hickory. 

LUMBERING. 

% 

Hickory  is  cut  either  by  small  portable  mills,  which  saw  only  hick- 
ory or  hickory  and  oak,  and  move  on  when  the  supply  is  exhausted, 
or  in  the  case  of  spokes  and  handles  or  round  bolts,  cut  by  farmers 
and  contractors  who  rive  out  the  billets  in  the  woods,  or  ship  the 
round  bolts  to  some  central  stationary  mill. 

The  portable  mill  commonly  cuts  material  for  rims,  poles,  and 
shafts.  It  requires  much  skill  to  work  up  the  hickory  properly,  so 
the  mills  are  generally  run  by  men  who  have  made  it  a  life  work. 
These  small  mills  cut  the  wood  into  rough  strips  to  be  shipped  to 
larger  stationary  mills  for  finishing.  The  cost  for  logging  and  lum- 
bering hickory  is  greater  than  that  for  any  other  common  native 
hardwood.  It  takes  much  time  and  trouble  to  locate  and  buy  it 
because  it  can  rarely  be  secured  in  large  lots;  because  of  the  widely 
scattered  supply  the  mill  must  be  moved  a  great  many  times  or  the 
logs  brought  long  distances;  the  wood  is  hard  to  cut  and  heavy  to 
haul,  and  there  is  a  great  amount  of  waste  at  the  mill — 40  per  cent 
or  more  of  the  timber  that  reaches  the  mill.  In  addition,  rough  stock 
must  always  be  shipped  green,  and  that  makes  high  freight  bills. 
Altogether,  it  often  costs  twice  as  much  to  get  hickory  to  the  factory 
as  it  does  oak,  yet  hickory  plank,  cut  in  connection  with  other  oper- 
ations, brings  comparatively  low  prices  because  it  is  apt  to  be  cross- 
grained  and  has  a  tendency  to  check  and  split  when  it  is  not  worked 
up  immediately. 


LUMBERING.  11 

Spoke  billets  are  commonly  rived.  Rived  billets  are  preferred  by 
the  spoke  makers  and  bring  the  best  prices,  but  riving  is  wasteful. 
Skilled  hands  may  get  as  many  rived  spokes  out  of  a  given  bolt  as 
could  be  obtained  by  sawing,  but  fewer  cuts  are  taken  from  the  tree 
and  the  material  which  will  not  make  spokes  is  never  utilized,  except 
occasionally  for  firewood.  There  is  an  additional  waste  because 
heartwood  and  birdpecked  wood,  which  would  be  used  if  it  were  at 
the  mill,  is  generally  left  in  the  woods.  The  price  of  rived  spoke 
billets  in  Memphis,  Tenn.,  is  $14  per  1,000  billets  for  the  white  and 
$9  for  the  red.  In  southern  Indiana  the  prices  are  $22  and  $14. 
Sawed  billets  are  usually  about  one-third  less.  Much  waste  is 
avoided  when  the  tree  is  cut  into  round  bolts  of  the  proper  length 
and  these  are  hauled  or  shipped  to  the  mill  to  be  sawed.  Such  bolts 
bring  from  $7  to  $10  a  cord  delivered  at  the  mill  in  the  South,  and 
from  $10  to  $12  in  Ohio  and  Indiana.  A  cord  of  hickory  will  yield 
about  700  rived  spoke  billets,  or  900  sawed  ones,  or  from  250  to  300 
handle  blanks. 

STUMPAGE    PRICES. 

Next  to  black  walnut,  hickory,  according  to  the  census  returns,  is 
the  most  valuable  of  important  American  woods.  This  high  value 
is  due  in  part  to  the  inclusion  of  the  prices  of  special  stock  and  to  the 
greater  cost  of  lumbering.  Stumpage  prices,  however,  are.  in  most 
places,  still  comparatively  low,  generally  about  the  same  as  those  of 
oak.  In  the  South  the  common  price  is  from  $2  to  $5  per  thousand 
feet.  In  northern  Ohio,  according  to  the  location,  $15  to  $25  is  paid, 
and  in  eastern  Pennsylvania,  Maryland,  and  Virginia,  $15  to  $35  is 
common.  Oak  in  these  more  settled  districts  brings,  perhaps,  30 
per  cent  less. 

LOG   RULES. 

Except  where  hickory  bolts  are  actually  piled  and  sold,  the  crudest 
of  methods  are  used  for  measuring  hickory  logs  and  bolts.  Logs 
over  10  inches  in  diameter  are  usually  scaled  by  the  well-known 
Doyle  rule,  which,  in  spite  of  its  wide  popularity,  is  one  of  the  most 
inaccurate  of  all  log  rules. a  It  gives  values  which  are  too  high  for 
large  logs  and  very  much  too  low  for  small  logs.  On  a  conservative 
estimate  based  upon  a  number  of  mill  studies,  10-inch  logs  show  an 
overrun  of  as  much  as  70  per  cent  in  the  amount  of  rough  lumber 
which  they  will  yield;  15-inch  logs  of  40  per  cent;  20-inch  logs  of 
20  per  cent;  while  logs  more  than  30  inches  in  diameter  show  an 
underrun.  This  is  particularly  unfair  in  the  case  of  hickory  because 
the  sizes  are  usually  small,  and  in  an  average  lot  of  hickory  logs 

"Forest  Service  Bulletin  36,  "The  Woodsman's  Handbook;"  Forest  Service  Bul- 
letin 73,  "Grades  and  Amount  of  Lumber  Sawed  from  Yellow  Poplar,  Yellow  Birch, 
Sugar  Maple,  and  Beech;"  Report  of  the  New  Hampshire  Forestry  Commission  for 
1905-6. 


12  THE   COMMERCIAL  HICKORIES. 

there  will  be  an  overrun  of  40  per  cent  or  even  more.  Sometimes 
the  Scribner  rule  is  used,  but  even  it  is  unsatisfactory  and  fails  to 
give  the  smaller  sizes  their  just  values.  The  greatest  injustice 
exists  in  the  case  of  short  bolts  and  logs  under  10  inches  in  diameter. 
Hickory  butts  under  10  inches  in  diameter  are  commonly  sold  by 
the  linear  foot.  In  northern  Ohio  they  bring  5  cents  per  linear  foot, 
regardless  of  diameter.  In  southern  Ohio  a  sliding  scale  is  commonly 
used  by  which  the  number  of  cents  paid  per  linear  foot  is  2  less  than 
the  number  of  inches  in  the  diameter  of  the  log  at  the  small  end 
inside  the  bark.  This  is  better  than  taking  no  account  of  the  diam- 
eter, but  it  is  far  from  correct.  For  example,  a  10-inch  log  contains 
nearly  three  times  as  much  material  as  a  6-inch  log,  yet  the  price  is 
only  twice  as  great;  a  12-inch  log  contains  four  times  as  much  mate- 
rial as  a  6-inch  log,  but  the  price  is  only  two  and  a  half  times  as  much. 

Handle  and  spoke  bolts  are  commonly  sold  by  the  cord ;  but  since 
it  is  often  inconvenient  to  pile  the  wood  in  order  to  measure  it, 
various  other  devices  are  resorted  to.  One  common  method  is  to 
measure  the  diameters  of  the  30-inch  bolts  at  the  small  end  inside 
the  bark  and  add  these  diameters  together  until  a  total  of  32  feet 
is  reached.  This  is  called  a  cord.  Two  classes  are  generally 
made — bolts  between  6  and  8  inches  in  diameter  and  those  over  8 
inches.  Some  difference  is  made  in  the  price,  but  it  is  never  enough. 
In  one  place,  for  instance,  the  first  class  brought  $5  per  cord  and 
the  second  class  $7;  yet,  even  if  the  average  diameter  of  the  two 
classes  had  been  7  and  9  inches,  the  ratio  should  have  been  5  to  8. 
As  a  matter  of  fact,  the  average  diameter  of  the  second  class  was 
considerably  over  9  inches,  and  the  difference  should,  therefore,  be 
much  greater. 

In  some  cases  an  estimate  is  made  of  the  number  of  billets  which 
the  bolts  contain,  and  they  are  bought  at  so  much  per  thousand. 

The  result  of  present  methods  is  that  highest  values  are  given  to 
small  sizes  on  the  one  hand  and  to  the  largest  on  the  other,  while 
the  very  sizes  which  are  most  to  be  desired  and  which  in  the  future 
should  be  most  profitable,  the  logs  and  bolts  from  9  to  15  inches  in 
diameter,  are  given  the  lowest  values,  sometimes  by  as  much  as  25 
per  cent  or  more. 

WASTE. 

The  amount  of  merchantable  hickory  wasted  each  year  may  be 
conservatively  estimated  at  40  per  cent  of  the  total  cut.  It  con- 
sists both  of  waste  in  the  woods  and  waste  at  the  mill. 

The  greater  waste  is  in  the  woods  and  is  due  chiefly  to  unneces- 
sary restrictions  against  heartwood  and  birdpecked  wood.  Millions 
of  feet  of  good  hickory  are  cut  each  year  and  left  in  the  woods 
because  of  the  presence  of  a  few  birdpecks,  or  the  large  proportion 
of  heartwood  make's  it  unprofitable  to  market  it.  Such  waste  is 


THE  TREE  AND  ITS   FORMS.  13 

especially  great  where  spoke  billets  are  rived  out  in  the  woods  and 
only  white  billets  are  taken,  because  the  red  billets  bring  little  more 
than  half  as  much  as  the  white.  Another  source  of  waste  comes 
from  the  discrimination  against  the  wood  from  the  upper  cuts  of 
the  tree  in  favor  of  that  from  the  lower  cuts.  This  is  due  not  alone 
to  the  knottier  character  of  the  upper  logs,  but  also  to  the  prevalent 
opinion  that  the  wood  is  considerably  inferior  to  that  from  the 
lower  cuts.  The  practice  of  cutting  high  stumps  prevalent  in  the 
South  is  also  very  wasteful.  It  is  claimed  that  the  difficulty  of 
sawing  out  with  the  grain  makes  it  unprofitable  to  cut  below  the 
flare  of  the  butt;  therefore  small  trees  are  generally  cut  more  than 
a  foot  above  the  ground  and  large  trees  more  than  2  feet.  Some 
firms,  however,  cut  low  stumps  and  consider  that  the  greater  width 
of  the  sap  and  the  greater  toughness  of  the  wood  in  the  butt  is  a 
sufficient  offset  to  the  difficulty  of  sawing.  If  the  average  stump 
height — at  least  2  feet — were  reduced  only  8  inches,  as  would  easily 
be  possible,  there  would  be  saved  as  much  as  10,000,000  board  feet 
annually  on  the  total  cut. 

A  somewhat  unavoidable  waste  arises  from  the  taking  out  of 
special  products.  The  pole  and  shaft  or  the  sucker-rod  makers 
leave  a  lot  of  stuff  in  the  woods  which  would  make  good  handles  or 
spokes,  while  the  spoke  or  handle  makers  use  up  a  great  deal  of 
material  which  should  really  be  put  into  poles,  shafts,  rims,  or  sucker 
rods.  Even  where  economy  is  attempted  and  spoke  billets  or 
handle  blanks  are  cut  in  connection  with  poles,  shafts,  or  rims,  it 
is  often  difficult  to  dispose  of  the  by-product,  and  it  often  happens 
that  for  lack  of  a  market  thousands  of  feet  of  hickory  are  destroyed 
by  insects. 

Much  of  the  waste  at  the  mill  is  due  to  the  discrimination  against 
the  heart  wood  and  birdpecked  material.  Another  source  is  the 
practice  of  cutting  spoke  billets  and  rim  and  pole  and  shaft  strips 
unnecessarily  long.  This  is  especially  true  of  spoke  billets,  which 
are  cut  into  a  uniform  length  of  30  inches,  whereas  the  spoke  lengths 
range  from  18  to  24  inches. 

In  addition  to  the  waste  of  merchantable  material,  in  lumbering 
much  promising  young  growth  is  used  for  skids,  is  swamped  out,  and 
is  broken  by  falling  trees.  This  loss  is  hard  to  estimate,  but  it  is 
very  great,  and  will  seriously  affect  the  future  supply. 

THE   TREE    AND    ITS    FORMS. 

The  hickories  belong  to  the  same  family  as  the  walunts.  Botan- 
ically  they  represent  a  very  old  form  and  rank  among  the  earlier 
hard  woods.  The  genus  is  now  peculiar  to  North  America  and  is 
confined  almost  entirely  to  the  eastern  part  of  the  United  States, 
though  some  species  grow  in  Canada,  and  in  Mexico  it  is  represented 


14 


THE   COMMERCIAL   HICKORIES. 


by  an  indigenous  species  (Hicoria  mexicana)  and  by  the  pecan  and 
the  nutmeg  hickory. 

The  fruit  of  the  hickory  is  the  most  unmistakable  characteristic 
of  the  genus.  In  general  it  is  much  like  that  of  the  walnut  —  a  nut 
with  a  single  two-chambered  kernel,  each  chamber  partially  sepa- 
rated into  two  lobes.  The  shell,  however,  is  smooth  on  the  out- 
side, and  the  husk,  instead  of  being  entire,  splits  into  four  segments, 
usually  from  the  apex  to  the  base,  and  allows  the  nut  to  drop  out. 
In  size  and  shape,  and  in  other  ways,  the  nuts  vary  greatly  in  the 

different  species.  The 
nut  of  the  big  shellbark 
is  often  an  inch  and  a 
half  in  diameter  and  has 
a  thick,  hard  shell,  while 
that  of  the  bitternut 
and  the  water  hickory 
is  small,  only  about  J 
inch  in  diameter,  with  a 
thin  shell  and  thin  husk. 
The  best  known  forms 
are  the  pecans  and  the 
shagbarks,  which  form 
important  articles  of 
commerce.  The  big 
shellbark  and  the  mock- 
ernut  also  produce  edi- 
ble nuts,  but  those  of 
the  bitternut  and  water 
hickory  are  quite  astrin- 


FIG.  1.— Pecan  (Hicoria  pecan).    Twig,  natural  size;  leaf  and 
fruit,  one-third  natural  size. 


compound,  with  three 
to  fifteen  leaflets,  ar- 
ranged in  opposite 
pairs,  with  a  single  rather  larger  leaflet  at  the  end.  The  leaves  are 
arranged  alternately  on  the  twigs.  This  feature  offers  a  ready 
means  of  distinguishing  the  hickories  from  the  ashes,  which  have 
opposite  leaves.  The  pith  is  solid  and  not  chambered  as  in  the 
walnuts. 

The  hickories  are  characterized  by  a  very  strong  taproot.  In  no 
other  genus  in  this  country  is  the  taproot  developed  to  a  greater 
extent.  (See  PL  III,  fig.  1,  p.  16.)  The  size  of  the  taproot  varies, 
however,  with  the  species  and  with  the  situation.  It  has  its  great- 
est development  in  the  drought-enduring  species  and  in  the  drier 
situations.  In  wet  river  bottoms  the  taproot  is  not  so  well  developed. 


THE   TREE   AND   ITS   FORMS. 


15 


The  bark  varies  greatly  and  has  no  single  easily  distinguishable 
characteristic  common  to  the  genus.  The  reddish-brown  bark  of 
the  shagbark  scales  off  in  long  thin  strips,  and  is  so  characteristic 
that  it  can  not  be  mistaken.  (See  frontispiece.)  The  bark  of  the 
moekernut  is  light  gray  and  does  not  scale  off  at  all.  Between 
these  two  extremes,  there  are  all  degrees  of  scaliness,  and  within 
each  species  the  bark  varies  so  that  it  alone  is  not  a  safe  guide  in 
distinguishing  the  species. 

The  bud  characters  divide  the  hickories  into  two  distinct  groups — 
the  true  hickories  and  the  pecan  hickories.  The  true  hickories  are 
characterized  by  full, 
round  buds,  with  many 
overlapping  scales,  of 
which  the  inner  ones  are 
usually  hairy.  Buds  of 
the  pecans  are  generally 
thin  and  narrow  and 
have  no  overlapping 
scales,  but  are  covered 
by  two  closely  fitting 
ones  with  a  glandular 
surface.  This  natural 
distinction  is  further 
borne  out  by  other 
general  characteristics 
of  the  two  groups. 
The  nuts  of  the  pecan 
group  are  generally 
thin-shelled  and  thin- 
husked,  the  leaves  have 
from  7  to  15  compara- 
tively narrow  leaflets, 

the   bark    is    Only    mod-      FlG>  2-~ Water  hickory  (Htcoria  aquattca).    Twig,  natural  size; 

leaf  and  fruit,  one-third  natural  size. 

erately   scaly,   and  the 

wood  is  comparatively  weak  and  brash.  In  the  true  hickories,  the 
nuts  are  generally  hard-shelled  and  thick-husked,  the  leaves  have 
from  3  to  9  leaflets,  the  bark  is  generally  scaly,  and  the  wood  is 
strong,  hard,  and  tough.  This  group  furnishes  practically  all  the 
hickory  wood  of  commerce. 

There  is  still  much  difference  of  opinion  among  botanists  as  to 
the  number  of  species.  Some  botanists  distinguish  as  many  as  15. 
From  the  forester's  standpoint,  however,  the  extremely  minute  sub- 
division into  species  is  unnecessary  and  confusing.  The  newly  dis- 
tinguished species  closely  resemble  in  some  characters  the  older  types, 
so  that  it  is  difficult  for  even  trained  botanists  to  tell  them  apart. 


16 


THE  COMMERCIAL  HICKORIES. 


In  this  publication  these  more  recently  described  species  are  treated 
as  varieties  and  only  8  main  types  are  described;  of  these,  4  belong 
in  the  pecan  group  and  4  are  true  hickories. 


THE   PECAN   HICKORIES. 


PECAN. 

In  the  pecan  group,  the  true  pecan  (Hicoria  pecan)  is  the  most 
important  because  of  the  value  of  its  nuts.  The  pecan  is  the  largest 

member  of  the  genus. 
Sarge^records  a  height 
of  170*  feet  with  a  trunk 
from  5  to  6  feet  in  diam- 
eter. 

The  distinguishing 
characteristics  of  the  pe- 
can are  slender  branch- 
lets  terminated  by  long 
slender  buds  covered 
with  a  dark-brown  glan- 
dular pubescence,  resem- 
bling those  of  the  wal- 
nuts, leaves  with  9  to 
15  slender  leaflets,  and 
elongated,  edible  nuts 
about  1  inch  in  length 
with  thin,  ridged  husk 
and  thin,  brown,  bony 
shells.  The  bark  is  dark 
brown  in  color,  close  and 

FIG.  3.— Nutmeg    hickory    (Hicoria  myristicseformis).    Twig,     finely  ridged. 

natural  size;  leaf  and  fruit,  one-third  natural  size.  -^  -...        .. 

Pecan    cultivation    is 

now  receiving  considerable  attention,  especially  in  the  Gulf  States, 
and  a  number  of  improved  varieties  are  being  introduced.  Most  of 
the  nuts  of  commerce,  however,  still  come  from  forest  trees  in 
Louisiana  and  Texas. 

WATER    HICKORY. 

The  water  hickory  (Hicoria  aquatica),  commonly  known  as  the 
"bitter  pecan,"  bears  a  strong  resemblance  to  the  pecan,  especially 
in  the  buds,  twigs,  and  leaves.  The  bark,  however,  is  more  scaly 
and  is  light  gray  in  color,  and  the  fruit  will  readily  distinguish  it 
from  any  other  hickory.  It  is  usually  about  an  inch  long.  The 
husk  is  thin  and  splits  to  the  base,  and  the  shell  is  soft  and  thin.  The 
nut  is  flattened,  often  sharply  angled,  and  the  kernel  is  very  bitter. 


Bui.  80,  Forest  Service,  U.  S.  Dept.  of  Agriculture. 


PLATE 


FIG.  1.— SPOKE  BOLTS  CUT  FROM  PIGNUT  HICKORY. 

[This  shows  a  close  use  of  material;  the  stump  is  cut  low  and  the  tree  utilized  well  into  the  top. 
The  28-inch  bolts  will  be  hauled  to  the  mill  and  there  cut  into  billets.    Orange  County,  Ind.] 


FIG.  2.— WASTE  IN  HICKORY  BOLTS  CUT  FOR  SPOKES. 
[This  shows  the  typical  waste  in  the  stump  and  in  the  material  left  in  the  woods.    Delhi,  La.] 


Bui.  80,  Forest  Service,  U.  S.  Dept.  of  Agriculture. 


PLATE  III. 


THE   TREE   AND   ITS   FORMS. 


17 


The  bitter  pecan  is  generally  a  small  tree  and  seldom  reaches  a 
diameter  of  more  than  2  feet,  though  it  frequently  forms  a  long 
clear  hole. 


NUTMEG    HICKORY. 


The  nutmeg  hickory  (Hicoria  myristicseformis)  is  a  very  distinct 
species.  It  is  a  comparatively  small  tree,  and  rarely  attains  a  diame- 
ter of  more  than  2  feet.  The  bark  is  thin,  brownish  gray,  and  flakes 
off  in  short  plates.  The  twigs  are  slender  and  gray.  The  terminal 
buds  are  from  one-eighth  to  one-fourth  of  an  inch  long,  rounded 
and  obtuse,  and  not  long 
and  narrow  as  in  the 
pecan.  The  bud  scales 
are  covered  with  a  thick 
brown  or  yellowish- 
brown  pubescence.  The 
axillary  buds  are  much 
smaller  and  narrower 
than  the  terminals.  The 
leaves  are  composed  of 
from  5  to  1 1  narrow  leaf- 
ets,  which  are  brownish 
on  the  under  surface  and 
give  to  the  foliage  a  char- 
acteristic yellowish  or 
brownish  cast.  The  fruit 
is  less  than  an  inch 
long,  usually  slightly 
elongated.  The  husk  has 
4  wings  that  extend  from 
the  apex  to  the  base,  is 
only  one-eighth  of  an  inch 
thick,  and  generally  splits 
to  the  base.  The  nut  has  a  bony  shell  and  resembles  a  nutmeg  in 
size,  shape,  and  color.  The  kernel  is  sweet. 

BITTERNUT. 

Bitternut  (Ilicoria  minima)  is  commonly  known  through  its  range 
as  "pignut"  or  "pig  hickory,"  and  in  some  places  as  "willow  hick- 
ory." The  term  "bitternut"  is  almost  entirely  a  book  name,  and  is 
for  the  most  part  confined  to  botanies  and  to  students  of  botany.  This 
gives  rise  to  much  confusion.  The  tree  bears  a  strong  resemblance 
to  the  pecan  and  to  the  water  hickory,  especially  in  the  bud  charac- 
ters. The  twigs  are  slender  and  the  buds  are  long  and  narrow,  and 
the  valvate  bud  scales  are  covered  with  a  bright  yellow,  glandular 
pubescence,  and  are  the  most  characteristic  feature  of  the  tree.  The 
51762°— Bull.  80—10 3 


FIG.  4.— Bitternut  (Hicoria  minima) .    Twig,  natural  size;  leaf 
and  fruit,  one-half  natural  size. 


18 


THE   COMMERCIAL   HICKORIES. 


leaflets  are  from.  5  to  9  in  number,  dark  green  and  shiny  on  the 
upper  side,  generally  narrow,  and  sharply  toothed.  The  nut  is  less 
than  an  inch  in  diameter  and  is  inclosed  in  a  thin,  almost  papery, 
husk  which  splits  about  two-thirds  of  the  way  down  and  is  ridged 
at  the  4  sutures  or  lines  of  division.  It  is  smooth  and  thin  shelled, 
and  has  a  very  bitter  kernel. 

In  form  the  bitternut  is  tall  and  slender  with  a  generally  straight 
bole,  which  prunes  itself  more  readily  than  most  of  the  hickories. 
The  sapwood  is  characteristically  narrow,  seldom  over  H  inches 

wide    or    more    than    25 
years  old. 

THE    TRUE    HICKORIES. 

SHAGBABK. 

Among  the  true  hicko- 
ries the  common  shagbark 
(Hicoria  ovata),  so  called 
because  of  its  peculiar 
bark,  also  known  as 
"scalybark"  and  "shell- 
bark,"  is  the  most  widely 
known. 

Of  all  the  hickories,  the 
shagbark  is  the  most  dis- 
tinct in  its  appearance. 
As  its  name  suggests,  the 
bark  is  its  most  charac- 
teristic feature.  It  is 
smooth  on  small  trees  and 
grayish  in  color,  but  later 
scales  off.  On  old  trees  the  bark  becomes  a  dark  reddish-brown  and 
hangs  on  in  long  loose  strips  or  plates.  Different  trees  display  all 
degrees  of  shagginess.  The  closer-barked  trees  are  commonly  known 
as  " bastard"  shagbarks  and  are  preferred  by  the  spoke  and  handle 
maker. 

The  foliage  is  coarse  and  heavy,  and  there  are  5  broad  leaflets. 
The  twigs  are  coarse,  and  both  twigs  and  leaf  stalks  are  usually 
somewhat  hairy.  The  buds  are  large,  and  the  terminal  buds  are 
often  half  an  inch  long ;  they  are  acute  and  covered  with  dark- brown 
outer  scales.  The  nuts  are  the  small  hickory  nuts  of  commerce  and 
vary  considerably  in  size  and  thickness  of  shell.  The  husk  is  from 
one-eighth  to  three-eighths  inch  thick,  splits  to  the  base,  and  is  some- 
what depressed  along  the  sutures. 

The  shagbark  attains  large  size,  and  heights  of  from  130  to  140 
feet,  and  diameters  of  from  20  to  30  inches  are  fairly  common  in  the 


FIG.  5.— Shagbark  (Hicoria  ovata).    Twig,  natural  size;  leaf 
and  fruit,  one-third  natural  size. 


THE   TREE   AND   ITS   FORMS. 


19 


Cumberland  Mountains.  In  the  river  bottoms  along  the  Mississippi 
the  trees  grow  to  larger  diameters,  but  the  maximum  height  growth 
is  usually  less.  One  characteristic  of  the  tree  is  the  tendency  to  fork 
within  the  crown  into  two  or  three  prongs  at  from  one-half  to  two- 
thirds  the  height  of  the  tree. 

The  southern  shagbark  (Ilicoria  carolinse  septentrionalis)  is  a  re- 
cently distinguished  species  of  little  commercial  importance.  In 
contrast  with  the  common  shagbark,  it  has  a  more  slender,  graceful 
habit,  slenderer  and  globulous  twigs,  smaller,  more  acute  buds,  with 
black  outer  scales,  and  leaves  with  from  3  to  5  leaflets.  It  is 
fairly  common  in  a  limited  range  from  Delaware  to  northern  Georgia, 
around  the  base  of  the  Appa- 
lachians, and  in  southern 
Kentucky.  It  grows  on  the 
lower  slopes  of  the  hills,  es- 
pecially on  limestone  soils, 
and  in  the  river  bottoms. 


BIG    SHELLBARK. 


Very  similar  in  appear- 
ance to  the  common  shag- 
bark  is  the  big  shellbark, 
or  king  nut  (Hicoria  lacini- 
osa),  also  known  as  the  yel- 
low twig,  big-fruited  shell- 
bark,  and  river  hickory. 
Lumbermen  rarely  differ- 
entiate between  the  two 
species,  although  they  are 
quite  distinct. 

The  big  shellbark  usually 
has  the  same  scaly  bark  as 
the  shagbark,  though  some- 
times it  is  firm  and  strongly 
ridged,  as  in  the  mockernut 
of  the  lower  Mississippi  Valley.  The  leaves  are  rather  coarser  and 
heavier,  and  there  are  commonly  7  and  often  9  leaflets.  The  most 
important  distinguishing  features  are  the  large  thick-shelled  nuts, 
often  1£  inches  in  diameter,  strongly  ridged  and  usually  much  flat- 
tened, with  husks  one-fourth  and  three-eighths  of  an  inch  thick  that 
split  all  the  way  to  the  base  and  are  usually  depressed  at  the  sutures, 
and  the  stout,  buff,  or  light  orange-colored  branchlets.  These  two 
features  distinguish  it  from  any  of  the  other  hickories,  although 
occasional  hybrids  are  reported.  Another  striking  feature  of  the  tree 
is  the  presence  upon  the  twigs  of  the  previous  year's  growth  of  old 


FIG.  6.— Big  shellbark  (Hicoria  laciniosa).    Twig,  natural 
size;  leaf  and  fruit,  one-fourth  natural  size. 


20 


THE    COMMERCIAL   HICKORIES. 


leaf  stocks,  in  many  cases  so  numerous  as  to  resemble  "  witches 
broom." 

In  habit  the  big  shellbark  is  rather  shorter  and  has  heavier  branches 
than  the  shagbark.  Generally  it  is  a  smaller  tree,  though  in  south- 
eastern Missouri  it  attains  a  height  of  from  120  to  130  feet  and  a 
diameter  of  40  inches  breast-high. 


PIGNUT. 


In  botanies  and  tree  manuals  the  name  commonly  given  to  Ilicoria 
glabra  is  "  pignut."  A  tremendous  amount  of  confusion  results  from 
this,  because  in  common  usage,  throughout  the  whole  range  of  the 

hickories,  the  term  pignut  is 
applied  to  an  entirely  differ- 
ent tree  (Hicoria  minima). 
The  names  in  common  use  in 
the  order  of  their  frequency 
are  black  hickory,  tight 
bark,  switch-top,  or  simply 
hickory. 

Of  all  the  hickories  none 
is  more  important  and  none 
offers  more  difficulties  to  the 
botanist.  It  is  exceedingly 
variable  and  grows  under 
widely  differing  conditions 
of  soil  and  climate.  Be- 
tween four  types  or  vari- 
ants, which  recently  have 
been  segregated,  there  are 
many  intermediate  forms. 

FIG.  7. -Pignut  (Hicoria  glabra).    Twigs,  natural  size;  leaf          Jn  ^he    typical  qlobrCL  the 
and  fruit,  one-third  natural  size.  .  J  * 

bark  is  generally  dark  gray 

in  color,  and  is  somewhat  flaky  or  scaly,  but  never  scales  off  in 
long  plates  like  the  shagbark.  In  old  trees  it  is  strongly  ridged,  much 
as  that  of  white  ash  or  elm.  The  leaflets,  leaf  stalks,  twigs,  and 
buds  are  entirely  free  from  hairs.  The  branchlets  are  slender  and 
the  buds  small.  There  are  from  5  to  7  leaflets.  The  fruit  is  generally 
pear-shaped  and  the  husk  splits  less  than  halfway  to  the  base.  The 
nut  is  smooth  and  round,  with  a  thin  shell.  The  kernel  is  likely  to 
be  sweet,  but  is  not  easy  to  get  out. 

The  variety  microcarpa,  which  is  the  common  one  of  the  Ohio 
Valley  and  which  many  botanists  now  describe  as  a  distinct  species, 
has  rather  coaser  twigs  than  the  typical  glabra.  The  fruit  is  smaller 
and  is  less  frequently  pear-shaped;  the  husk  commonly  splits  freely 


THE   TREE   AND   ITS   FORMS. 


21 


to  the  base  and  the  bark  is  likely  to  scale  off  in  flat  scales,  somewhat 
like  shagbark,  though  much  less  pronounced.  Some  botanists  also 
distinguish  another  variety,  odorata,  which  differs  in  having  larger 
nuts,  and  a  yellowish  glandular  pubescence  in  the  buds,  leaves,  and 
twigs. 

The  pale-leaf  hickory  (Hicoria  villosa)  is  a  distinct  species,  but  it 
also  may  be  placed  in  the  pignut  group.  It  is  a  xerophytic,  or  drought- 
resistant,  species,  and  grows  mainly  in  Arkansas  and  Missouri.  It 
resembles  the  mockernut  in  many  characteristics  and  particularly  in 
the  bark,  which  is  likely  to  be  deeply  fissured  and  rough,  but  not 
shaggy,  and  has  diamond-shaped  checks,  as  in  the  Mississippi  Valley 
form  of  the  mockernut. 
The  twigs  are  slender,  and 
twigs,  buds,  and  leaves  are 
covered  with  a  yellowish 
pubescence.  There  are 
from  7  to  9  leaflets,  gener- 
ally small,  narrow,  thick, 
dark  green,  and  shiny  on 
the  upper  side.  The  fruit 
varies  considerably  both  in 
size  and  shape  and  often 
resembles  that  of  the  mock- 
ernut; but  typically  it  is 
spherical,  with  a  moder- 
ately thin  husk,  slightly 
ridged  at  the  sutures,  and  a 
thick-shelled,  rounded  nut, 
much  like  that  of  pignut 
or  mockernut.  The  tree  is 
rarely  more  than  60  or  70 
feet  high.  Another  species, 
pallida,  resembles  the  vil- 
losa very  closely.  It,  also,  is  a  xerophytic  species,  and  grows  on 
the  hills  of  Tennessee,  Kentucky,  and  North  Carolina.  It  has  the 
same  yellowish  pubescence  on  twigs,  buds,  and  leaves,  except  that 
on  the  leaves  the  pubescence  is  rather  more  woolly.  The  fruit  also 
is  similar,  but  is  somewhat  more  winged.  Frequently  the  bark  is 
broken  into  small  cubes  somewhat  like  those  of  the  black  gum. 

MOCKERNUT. 

The  mockernut  (Hicoria  alba),  known  also  as  the  "big  bud," 
"white  heart/'  "white  hickory,"  and  "hognut,"  is  most  easily  recog- 
nized by  its  coarse,  hairy  leaves  and  twigs.  The  leaves  have  gen- 


FIG.  8.— Small  pignut    (Hicoria  odorata).    Twig,  natural 
size;  leaf  and  fruit,  one-half  natural  size. 


22 


THE   COMMERCIAL  HICKORIES. 


erally  from  7  to  9  leaflets.  The  fruit  varies  greatly  in  size  and  shape, 
but  commonly  is  spherical,  with  a  thick  husk  and  a  thick-shelled  nut, 
sometimes  strongly  ridged  and  sometimes  rounded,  that  contains  a 
small,  rather  rich  kernel.  The  bark  of  the  tree  is  never  scaly.  The 
characteristic  form  in  the  lower  Mississippi  Valley  has  deep,  diamond- 
shaped  checks  or  fissures  and  is  light  gray  in  color.  Farther  east  the 
bark  becomes  less  ridged  and  the  color  is  more  whitish.  The  sapwood 
is  wide — about  3  inches — and  is  generally  more  than  50  years  old. 
The  mockernut  generally  is  smaller  than  either  shagbark  or  pignut. 

The  stem  is  less  likely  to  be 
straight,  and  the  branches 
are  heavier. 

RANGE    AND   DISTRIBUTION. 

In  the  forest  the  hicko- 
ries are  rarely  predomi- 
nant. Except  through  the 
interference  of  man,  they 
do  not  grow  in  pure  stands 
but  always  in  mixture, 
somewhat  group-wise, 
with  other  species,  and 
especially  with  the  oaks. 
The  accompanying  maps 
show  the  botanical  and 
commercial  ranges  of  the 
different  species  of  the 
pecans  and  of  the  true 
hickories. 

The  botanical  ranges  show  the  regions  in  which  the  species  grow 
naturally. 

The  three  salient  points  of  the  botanical  distribution  are  the  com- 
paratively narrow,  southern  range  of  the  pecan  hickories  (except  the 
frost-hardy  bitternut),  confined  by  the  need  for  warmth  and  moisture 
to  the  river  bottoms  of  the  Mississippi  Valley  and  Gulf  regions;  the 
wide  distribution  of  the  true  hickories,  especially  the  pignut  and  the 
shagbark ;  and  the  centering  of  the  distribution  of  nearly  all  the  species 
in  the  lower  Mississippi  Valley,  in  western  Tennessee,  eastern  Arkan- 
sas, and  northwestern  Mississippi. 

The  commercial  distributions  show  the  regions  within  which  the 
hickory  is  of  sufficient  importance  to  be  a  factor  in  forest  manage- 
ment. Of  all  the  species,  shagbark  and  pignut  are  most  widely  and 
evenly  distributed,  and  these  two  furnish  the  bulk  of  the  hickory  of 
commerce.  Shagbark  is  fairly  common  in  the  wood  lots  of  southern 


FIG.  9.— Mockernut  (Hicoria  alba).    Twig,  natural  size;  leaf 
and  fruit,  one-third  natural  size. 


THE   TREE  AND   ITS   FORMS. 


23 


New  England  and  New  York,  and  becomes  more  prominent  westward 
through  southern  Pennsylvania  and  West  Virginia.  In  northern 
Ohio  and  Indiana,  in  the  lower  Ohio  Valley,  and  in  the  river  bottoms 
of  the  lower  Mississippi  Valley  it  is  the  commonest  of  the  hickories. 
Since  most  of  the  remaining  virgin  hickory  is  in  the  lower  Mississippi 
Valley,  and  since  cutting  is  now  especially  heavy  there,  it  is  probable 
that  most  of  the  hickory  on  the  market  is  shagbark. 


Nutmeg  hickory. 


Bitternut. 


FIG.  10.— Ranges  of  the  pecan  hickories.    The  light-shaded  areas  show  the  botanical  ranges;  the 
darker  areas,  the  commercial  ranges. 

The  commercial  distribution  of  pignut  corresponds  closely  to  that 
of  shagbark,  except  that  it  extends  farther  toward  the  coast  in  the 
southeast.  West  of  the  Mississippi  it  is  represented  chiefly  by  the 
pale-leaf  hickory  (villosa)y  which,  because  of  its  small  size,  is  as  yet  but 
little  cut.  Pignut  is  most  prominent  in  the  Cumberland  Mountains 
of  Tennessee,  Kentucky,  and  West  Virginia,  and  on  the  hills  of  the 
Ohio  Valley.  In  these  regions  it  furnishes  most  of  the  cut. 

Mockernut  is  characteristically  a  southern  species.  It  is  fairly  com- 
mon in  southeastern  Pennsylvania  and  New  Jersey,  and  becomes  more 


24 


THE    COMMERCIAL   HICKORIES. 


prominent  toward  the  South  through  Virginia,  North  Carolina,  and 
Florida,  where  it  is  the  commonest  of  the  hickories  and  furnishes  the 
bulk  of  the  cut.  It  is  abundant  in  the  lower  Mississippi  Valley,  but  is 
commercially  less  important  than  shagbark. 

Big  shellbark  has  a  narrow  commercial  distribution.  It  is  most 
prominent  in  the  region  around  the  lower  Ohio  River,  south  along  the 
Mississippi  to  central  Arkansas,  and  northeast  through  the  Wabash 
Valley  to  northern  Indiana  and  Ohio. 


Shagbark. 


Big  shellbark. 


r.-A 


Pignut.  Mockernut. 

FIG.  11.— Ranges  of  the  true  hickories.    The  light-shaded  areas  show  the  botanical  ranges;  the  darker 

areas,  the  commercial  ranges. 

The  pecan  hickories  can  not  be  said  to  be  of  commercial  importance, 
because  they  are  seldom  cut.  Bitternut  is  fairly  common  from  south- 
ern New  England  west  to  Iowa  and  from  southern  Michigan  south  to 
Kentucky.  South  of  Kentucky  it  is  somewhat  rare.  Pecan  grows 
as  far  north  as  Dubuque,  Iowa,  but  is  rare  and  local  north  of  the  Ohio 
River.  Along  the  Mississippi,  southward  from  the  mouth  of  the  Ohio, 
it  grows  gradually  more  common,  until,  in  southern  Arkansas  and  in 
Louisiana,  it  becomes  an  important  factor  in  the  forest.  It  is  also 


THE    TBEE   AND    ITS    FORMS.  25 

common  in  eastern  Texas.  The  water  hickory  is  common  only  along 
the  lower  Mississippi  and  in  eastern  Texas,  and  nutmeg  hickory,  the 
rarest  of  them  all,  grows  mainly  in  southeastern  Arkansas. 

SOIL    AND    MOISTURE    REQUIREMENTS. 

In  general,  the  hickories  are  exacting  in  their  soil  requirements, 
though  in  this  respect  there  is  a  wide  variation  within  the  genus. 
Stunted  mockernuts  grow  in  Alabama  and  'Mississippi  upon  the 
sandy  shortleaf  and  loblolly  pine  land;  the  drought-enduring  pale- 
loaf  hickory  grows  on  the  dry  hillsides  of  western  Arkansas  and 
Missouri;  pignut  and  mockernut  grow  in  dry  situations,  such  as  west 
and  south  slopes,  or  dry  ridges  in  the  Cumberlands,  or  the  knobs  of 
southern  Indiana.  In  all  these  drier  situations,  however,  the  trees 
are  likely  to  be  stunted,  defective,  and  usually  badly  bird  pecked; 
even  the  drought-enduring  species  requires  for  good  development 
soils  that  are  moderately  fresh  and  fertile.  Most  of  the  merchantable 
mockernut  and  pignut  grows  on  fairly  fertile  uplands  with  white  oak, 
black  oak,  scarlet  oak,  and  post  oak,  and  the  very  best  development 
is  attained  only  on  fresh,  deep,  fertile  soil.  Pignut  in  particular 
responds  readily  to  the  increased  fertility  of  the  soil,  and  in  the  coves 
of  the  Cumberland  Mountains,  associated  with  white  oak,  red  oak, 
yellow  poplar,  basswood,  buckeye,  white  ash,  beech,  maple,  and  shag- 
bark,  it  is  the  largest  of  the  hickories.  On  the  river  bottoms  of  the 
Mississippi  it  attains  larger  dimensions  than  -any  other  hickory, 
except  the  pecan. 

At  the  other  extreme,  water  hickory  grows  with  cypress  where  the 
ground  is  wet  all  the  year  round  and  water  stands  during  most  of  the 
year.  Pecan  and  nutmeg  hickory  are  only  a  little  less  moisture 
loving.  They  grow  usually  on  the  overflow  lands  of  the  South,  asso- 
ciated with  sweet  gum,  tupelo,  white  oak,  cow  oak,  overcup  oak, 
white  and  blue  ash,  and  but  rarely  grow  in  drier  situations  except 
when  planted  there.  Big  shellbark  and  bitternut  also  are  moisture- 
loving  species.  The  former  grows  usually  in  river  bottoms  or  on  the 
banks  of  streams  throughout  its  range,  associated  with  elm,  white 
ash,  white  oak,  cow  oak,  overcup  oak,  and  shagbark  hickory;  the 
latter,  which  has  a  more  northern  distribution,  grows  along  streams, 
on  rich  bottom  lands,  and  on  north  and  east  slopes  associated  with 
elm,  white,  red,  and  pin  oak,  white  ash,  shagbark  and  big  shellbark 
hickory.  The  widely  distributed  shagbark  shows  to  a  marked  degree 
the  tendency  to  seek  moister  situations  in  its  southern  range  and 
drier  ones  to  the  north.  In  the  Ohio  Valley  it  grows  chiefly  on  fertile 
uplands  on  north  and  east  slopes;  in  the  Cumberlands  it  is  con- 
fined to  the  coves  and  to  north  and  east  slopes.  At  lower  elevations 
southward  it  seeks-  moister  situations,  and  in  Arkansas,  Mississippi, 
and  Louisiana  grows  only  in  the  river  bottoms.  Throughout  its 
range  shagbark  is  commonly  associated  with  white  oak  and  white  ash, 
517G20— Bull.  SO— 1( 


26  THE   COMMERCIAL   HICKORIES. 

and  in  the  Cumberland  Mountains  grows  also  with  red  oak,  yellow 
poplar,  basswood,  buckeye,  beech,,  and  sugar  maple. 

In  their  soil  and  moisture  requirements,  beginning  with  those  which 
require  least  moisture,  the  hickories  rank  as  follows:  Pignut,  mocker- 
nut,  shagbark,  bitternut,  big  shellbark,  nutmeg  hickory,  pecan,  water 
hickory. 

TOLERANCE. 

Most  hickories  require  but  little  light  in  early  life,  and  grow  under 
fairly  dense  shade.  A  peculiar  feature  of  the  tolerance  of  hickories 
is  the  remarkable  rapidity  with  which  they  recover  from  suppression. 
After  being  suppressed  for  from  sixty  to  eighty,  or  even  one  hundred 
years,  during  which  time  they  reach  diameters  of  only  a  few  inches, 
they  are  able  to  respond  to  the  stimulus  of  increased  light  and  imme- 
diately begin  to  expand  their  crowns  and  put  on  heavy  layers  of  wood. 
A  tree  which  has  been  suppressed  and  is  then  freed  by  an  opening  in 
the  forest  cover  will  often  develop  at  a  faster  rate  of  growth  than  that 
of  a  normal  tree  of  the  same  size  and  diameter  which  has  never  been 
suppressed.  This  capacity  for  enduring  shade  is  so  strong  in  pignut 
and  shagbark  that  the  largest  diameter  increase  may  come  at  the  age 
of  150  or  even  200  years. 

In  short,  big  shellbark  and  pignut  are  only  slightly  less  tolerant 
than  sugar  maple  and  beech  of  those  trees  which  grow  in  the  central 
hardwood  belt.  This  tolerance  is  common  to  the  whole  genus,  though 
different  species  show  varying  degrees  of  tolerance ;  the  true  hickories 
are  all  more  tolerant  than  the  pecans.  In  the  order  of  tolerance  from 
those  which  require  least  to  those  which  require  most  light,  they  rank 
as  follows:  Pignut,  shagbark,  big  shellbark,  mockernut,  bitternut, 
nutmeg  hickory,  pecan,  water  hickory. 

The  great  shade-enduring  capacity  of  most  of  the  hickories  is  of 
the  utmost  importance  to  reproduction,  for  to  this  capacity  is  due  the 
ability  of  the  tree  to  hold  its  own  in  the' forest. 

REPRODUCTION. 

Hickory  is  reproduced  both  by  seed  and  by  sprout.  Seedling 
r?production,  even  in  the  virgin  forest  and  under  dense  shade,  is 
made  possible  by  the  great  tolerance  of  the  young  trees.  The  nuts 
are  borne  at  irregular  intervals,  but  good  seed  years  come  practically 
every  other  year.  Nuts  are  seldom  borne  by  trees  under  5  inches  in 
diameter.  Thrifty  hickories  standing  in  the  open  will  frequently  bear 
as  many  as  2  or  even  3  bushels  of  shelled  nuts  in  a  year,  and  improved 
varieties  of  pecans  will  bear  15  bushels.  Only  a  small  proportion  of 
the  seed  is  left  to  germinate,  however,  because  squirrels,  mice,  hogs, 
and  man  eat  great  quantities  of  the  nuts,  especially  of  the  sweet- 
kerneled  pecans  and  shagbarks.  Squirrels  especially  are  to  be 
reckoned  with,  not  altogether  as  enemies,  but  as  friends;  although 


THE   TREE   AND   ITS    FORMS. 


27 


they  live  upon  the  nuts,  they  also  bury  them  in  the  ground,  and  it  is 
largely  through  the  agency  of  squirrels  that  the  nuts  are  carried  out 
from  under  the  shade  of  the  parent  tree,  and  the  hickories  thus  get 
a  foothold  in  territory  where  seed  trees  are  lacking. 

During  the  first  few  years  the  seedling  spends  most  of  its  energy 
in  developing  a  taproot.  Measurements  of  32  seedlings  growing  in 
heavy  red  clay  soil  showed  that  at  one  year  the  average  shagbark  had 
a  root  about  12  inches  long,  the  bitternut  11  inches,  and  the  big 
shellbark  13  inches.  At  3  years  of  age  the  root  of  the  big  shellbark 
is  about  2^  feet  long  and  the  roots  of  the  other  hickories  are  about 
the  same  length. 

The  height  growth  of  seedlings  in  the  Ohio  Valley  in  the  open  or 
under  light  shade,  on  red  clay  soil,  is  shown  in  Table  1. 

TABLE  1. — Height  growth  of  seedlings. 


Age  —  years. 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

Height—  inches. 

Shagbark 

2.8 
3.0 
3.0 
3.5 
4.3 
6.4 

4.2 
5.8 
4.7 
6.3 
6.0 
12.0 

7.8 
8.0 
8.0 
9.5 
11.0 
19.0 

12.0 
12.0 
12.5 
13.3 
16.0 
28.0 

17.0 
17.0 
20.0 
19.5 
22.0 

Pignut  

Mockernut 

28.0 
27.0 

Bitternut 

Big  shellbark 

Pecan  

This  table  is  not  based  on  a  sufficient  number  of  seedlings  to  be 
entirely  conclusive,  but  it  shows  the  relatively  rapid  growth  of  pecan 
and  big  shellbark  and  the  slow  growth  of  shagbark,  pignut,  and 
mockernut. 

Seedlings  of  large  size  are  rare  because  seedlings  usually  meet  with 
an  accident  which  kills  them  back  and  puts  them  in  the  class  of 
" seedling  sprouts."  Fire  and  pasturing  are  the  chief  sources  of  such 
accidents,  which,  however,  are  not  unmixed  evils,  because  young 
hickory  sprouts  readily,  and  the  stool  quickly  sends  out  rapid-growing 
shoots  that  are  generally  straighter  than  the  original  seedling.  Hick- 
ory is  a  very  persistent  sprouter  when  young.  The  sprouts  will  stand 
heavy  shade  and  will  come  up,  time  after  time,  undiscouraged  by 
repeated  burnings  and  cutting  back.  In  this  property  hickory  excels 
all  other  hardwoods  of  the  central  hardwood  region.  Partly  through 
this  and  partly  through  the  fact  that  hickory  is  one  of  the  last  trees 
which  cattle  will  eat,  large  areas  of  pasture  land,  especially  in  Ohio 
and  Indiana,  are  occupied  by  pure  stands  of  hickory  sprouts.  Occa- 
sionally, also,  abandoned  fields  are  so  occupied.  In  both  cases  such 
stands  are  usually  too  open,  and  the  trees  are  scrubby  and  knotty. 

Throughout  the  Ohio  Valley  and  the  central  hardwood  region  gen- 
erally, there  is  excellent  reproduction  of  hickory  in  thickets  under  the 


28 


THE   COMMERCIAL   HICKORIES. 


older  stands,  and  most  of  the  saplings  are  seedling  sprouts.  In  the 
river  bottoms  of  the  South,  however,  the  reproduction  generally  is 
poor;  this  may  be  due  to  the  fact  that  the  ground  is  covered  with  water 
during  the  winter  and  the  nuts  are  washed  away,  or  to  the  fact  that 
the  stumps  seem  to  sprout  less  readily  in  this  region,  or  to  the  large 
number  of  hogs  to  eat  the  nuts. 

Most  of  the  hickories  now  standing  are  either  seedlings  or  sprouts 
from  small  stumps.  Coppice  hickory  is  not  nearly  as  common  as 
coppice  chestnut  or  oak,  because  hickories  are  slow-growing  and  their 
sprouting  capacity  diminishes  rapidly  with  age;  trees  which  have 
reached  merchantable  size  can  not  be  depended  on  to  produce  sprouts. 
Furthermore,  hickory  sprouts  grow  more  slowly  than  those  of  other 
broad-leaf  trees,  and  can  not  compete  with  them  in  even-aged  stands. 

Sprouts  may  grow  from  the  stump,  the  root  collar,  and  the  root. 
Stump  sprouts  are  exceptional;  and  the  tendency  toward  root  sprouts, 
or  suckers,  increases  with  the  size  and  age  of  the  tree.  Table  2,  based 
on  measurements  of  183  stumps  of  shagbark  hickory,  shows  that  as 
the  stumps  increase  in  size,  the  number  that  produce  sprouts  decreases, 
and  that  the  proportion  of  root  suckers  increases. 

TABLE  2. —  Vigor  and  method  of  sprouting  with  increase  in  diameter  of  stump  in  shagbark 

hickory. 


Diameter  of  stump. 

Stumps 
producing 
sprouts. 

Sprouts 
from 
stump. 

Sprouts 
from 
collar. 

Sprouts 
from  root. 

Height  of 
sprouts 
1  year  old. 

Inches: 

2 

Per  cent. 
100 

Per  cent. 
12  0 

Per  cent. 
88 

Per  cent. 
0  0 

Feet. 
3  15 

3  .   ... 

100 

11.0 

85 

6.0 

3.10 

4 

100 

10  0 

76 

14  0 

3  05 

5  

100 

9.0 

70 

21.0 

3.00 

6 

100 

8  0 

64 

28  0 

2  95 

7  

100 

7.5 

58 

34.5 

2.90 

8 

100 

7  0 

52 

41  0 

2  80 

9  

92 

6.0 

45 

49.0 

2.75 

10                    .   . 

85 

5.0 

40 

55  0 

2.70 

11 

75 

4  5 

35 

61  0 

2  65 

12  

66 

4.0 

30 

66.  0 

2.  60 

13 

56 

3  5 

25 

71  5 

2  55 

14  

47 

3.0 

22 

75.0 

2.50 

15 

37 

2  5 

19 

78  5 

2  40 

16  

26 

2.0 

17 

81.0 

2.30 

17 

17 

1  5 

17 

82  5 

2  15 

Of  northern  species  bitternut  is  the  best  sprouter,  and  the  average 
height  of  dominant  1-year-old  sprouts  from  20  stumps  was  4.7  feet. 
One-year-old  sprouts  from  31  stumps  of  pignut  showed  an  average 
height  of  3.3  feet  as  against  an  average  of  2J  feet  for  the  183  stumps, 
of  shagbark,  though  there  is  but  little  difference  in  the  sprouting 
capacity  of  the  two  species. 

The  distance  of  the  root  suckers  from  the  stump  increases  with  the 
size  of  the  stump.  The  maximum  distance  is  about  8  feet  and  the 
average  about  2  feet.  As  a  rule,  the  sucker  does  not  produce  a  tap- 
root but  merely  appropriates  the  parent  root. 


THE   TREE   AND   ITS   FORMS. 


29 


GROWTH. 

The  hickories  are  comparatively  slow-growing,  especially  the  true 
hickories.  Pecan  grows  rather  rapidly,  is  long-lived,  and  is  persistent 
in  its  growth;  the  bitternut  grows  rapidly  at  the  start,  though  it  rarely 
reaches  large  size.  The  true  hickories,  however,  are  even  slower-grow- 
ing than  white  oak.  A  200-year-old  white  oak  growing  under  the 
same  conditions  of  light  and  soil  as  a  shagbark  or  pignut  of  the  same 
age  often  will  have  almost  twice  the  diameter  and  will  yield  from  two 
to  four  times  as  much  .merchantable  material.  No  growth  figures 
were  secured  for  pecan,  water,  or  nutmeg  hickory,  since  they  are  unim- 
portant commercially,  and  no  cuttings  were  found.  Figures  for  the 
other  species  were  taken  for  typical  situations  in  five  different  regions. 

As  previously  shown,  the  hickories  are  generally  suppressed  in  early 
life.  Therefore,  to  secure  figures  that  would  be  applicable  to  trees 
grown  under  forest  management,  the  periods  of  suppression  have  been 
disregarded  in  the  preparation  of  Table  3,  which  gives  the  time 
required  for  a  normal  tree  to  increase  1  inch  in  diameter. 

TABLE  3. —  Time  required  by  trees  of  various  diameters  to  make  1  inch  of  diameter  growth. 


Diameter 
breast-high. 

Eastern 
Maryland 
and  Penn- 
sylvania. 

Ohio  Valley. 

Northern 
Ohio. 

I 

Cumberland 
Mountains. 

Mississippi  Valley. 

I 

fc 

.U 

3 

M 

1 

I 

h 

1 
I 

i 

d 

s 

1 

£ 

M 

I 
| 

,13 

CQ 

+z 
a 
d 

bo 

£ 

M 

"I 

i 

3 

M 

g 

I 

K 

24 
1 

i 

g 

+; 

3 

1 

1 

! 

Inches: 
1  

Yrs. 
11 
11 
10 
9 

8 
8 
8 

7 

7 

7 
7 
6 

6 
6 
6 
6 

6 
6 
6 
6 

6 

6 

6 
0 

7 

7 

Yrs. 

10 

8 
8 

7 

7 
G 
6 
6 

6 
6 
6 
6 

6 

7 
7 
7 

8 
8 
8 

8 
8 
9 
9 

10 

Yrs. 
9 

8 
8 
8 

7 
7 
7 
7 

7 
7 

7 
7 

7 
8 
8 
8 

8 
8 

Yrs. 
9 
9 

8 
8 

8 
8 
8 
8 

8 
8 
8 
8 

8 
8 
8 
8 

8 
8. 

Yrs. 
9 

8 
8 
7 

7 
6 
6 
6 

6 

7 
7 
7 

8 
8 
9 
10 

Yrs. 
11 
10 
9 

8 

8 
8 
8 
8 

8 
8 
8 
8 

8 
8 
8 
9 

9 
10 
10 
11 

11 
13 

Yrs. 

9 
9 
9 
9 

9 

8 
8 
8 

9 
9 
9 
9 

10 
10 
11 

Yrs. 
11 
11 
10 
10 

9 
9 

8 
8 

8 
8 
8 
8 

8 
8 
8 
8 

8 
8 
8 

8 
8 
8 

8 

8 
8 
8 
9 

Yrs. 
9 

8 
8 

8 

8 
8 
8 
8 

8 
8 
8 
8 

8 
8 
8 
8 

8 
8 
8 
8 

8 
8 
8 
8 

9 
9 
9 
9 

Yrs. 

8 
8 
8 
8 

8 
8 
8 
8 

8 
8 
8 
8 

8 
8 
8 

8 

8 
8 
8 
9 

9 
10 
10 
11 

Yrs. 
11 
10 
9 
8 

8 
8 
8 
8 

8 
8 
8 
8 

8 
8 
8 
8 

8 
8 
8 
8 

8 
8 
8 
8 

8 
8 
8 
8 

Yrs. 

8 
8 
8 

8 
8 
8 
8 

8 
8 
8 
8 

8 
8 
8 
8 

8 
8 
8 
8 

8 
8 

8 
8 

8 
7 

7 
7 

Yrs. 
7 

1 
7 
7 

7 
7 

7 

7 

7 

7 
7 
7 

7 
7 
7 
7 

7 
7 
7 
8 

8 
8 
8 
8 

8 
8 
8 
8 

Yrs. 
13 
11 
11 
11 

10 
10 
10 
9 

9 
9 
8 
8 

8 
8 
8 
8 

8 
8 
8 
8 

8 
8 
8 
9 

9 
10 

2. 

3  
4  

5... 

6.   .   .. 

7 

8  

9... 

10  

11 

12 

13 

14  

15  

16 

17  
18  
"    19  

20 

21.. 
22.,   .. 
23  

24  
25.. 

26... 

27  

7 

28  

7 

30 


THE   COMMERCIAL   HICKORIES. 


The  rapid  growth  shown  in  eastern  Maryland  and  Pennsylvania  is 
due  to  extremely  favorable  conditions.  The  trees  measured  were 
growing  on  agricultural  soils  of  excellent  quality,  deep  reddish  sandy 
loams  underlain  by  gneiss,  and  the  stands  had  been  opened  up  and 
growth  stimulated.  The  trees  measured  in  the  Mississippi  Valley 
and  Cumberland  Mountains  also  were  growing  on  good  soils,  the 
former  on  rich  alluvial  soils  of  river  bottoms,  and  the  latter  generally 
on  rich  north  and  east  slopes.  Their  slow  growth  is  due  to  their 
development  in  the  virgin  forest,  though  their  extreme  persistency 
indicates  that  under  management  their  growth  in  either  region  would 
be  as  fast  as  if  not  faster  than  in  eastern  Maryland.  In  the  Ohio 
Valley  the  trees  were  growing  on  low  hills  which  characterize  southern 
Indiana  and  northern  Kentucky,  on  less  favorable  soils,  mainly  red 
clay,  with  the  underlying  rock,  sandstone,  limestone,  or  slate.  The 
trees,  however,  were  strictly  second  growth.  In  northern  Ohio  the 
land  is  flat  and  is  underlain  by  a  stiff,  almost  impermeable  clay, 
which  keeps  the  top  soil  wet  most  of  the  year.  The  trees  measured 
were  strictly  second  growth. 

Pignut,  shagbark,  and  big  shellbark  hickories  show  similar  rates  of 
growth,  and  all  three  are  very  persistent.  Mockernut  and  bitternut 
grow  more  rapidly  at  first,  but  the  rate  soon  decreases  and  the  trees 
seldom  reach  large  size. 

Table  4,  made  up  from  measurements  of  second-growth  trees  in 
southern  Indiana  and  northern  Kentucky,  shows  approximately  what 
may  be  expected  from  hickory  grown  under  forest  management. 

TABLE  4. — Diameter  growth  of  normal  second-growth  hickory. 


Age. 

Diameter  breast-high  of— 

Pignut. 

Shagbark. 

Bitternut. 

Years: 
10 

Inches. 
1.0 
2.0 
3.2 
4.4 
5.5 
6.8 
8.4 
10.0 
11.4 

Inches. 
1.2 
2.8 
4.0 
5.4 
6.8 
8.0 
9.4 
10.5 
11.6 

Inches. 
2.0 
4.0 
6.0 
7.6 
9.2 
11.4 
13.0 

20  

30 

40  

50  

60 

70  

80  .                                          

90 

The  pignut  was  growing  on  only  moderately  good  soil,  the  shag- 
bark  on  soil  of  somewhat  better  quality,  and  the  bitternut  on  very 
good  soil.  Under  similar  soil  and  light  conditions  there  would  proba- 
bly be  little,  if  any,  difference  between  pignut  and  shagbark.  Bitter- 
nut,  however,  is  not  only  a  faster-growing  tree,  but  grows  characteris- 
tically on  the  richer  soils. 


THE   TREE   AND   ITS   FORMS. 


31 


Table  5  gives  figures  of  height  growth  of  a  few  carefully  selected 
trees  growing  under  soil  conditions  similar  to  those  of  the  trees  given 
in  Table  4. 

TABLE  5. — Height  growth  of  various  hickories. 


Age—  years. 

Ohio  Valley. 

North- 
ern 
Ohio. 

Cumberland  Mountains. 

Mississippi  Valley. 

Shag- 
bark. 

Pignut. 

Bitter- 
nut. 

Pignut. 

Shag- 
bark. 

Pignut. 

Mocker- 
nut. 

Shag- 
bark. 

Pignut 

Mocker- 
nut. 

Height—  feet. 

10... 

7 
18 
32 
43 
51 
58 
64 
70 
75 
79 

9 
19 
32 

42 
51 
58 
64 
69 

10 
24 
40 
52 
62 
69 

7 
20 
35 
48 
61 
69 
74 

3 
13 
4       20 
27 
34 
41 
48 
54 
60 
66 
78 
89 
99 
108 
116 

6 
14 
24 
32 
40 
48 
55 
62 
69 
75 
85 
93 
99 
104 
108 

4 

17 
26 
33 
39 
45 
50 
55 
60 
66 
76 
85 
94 
102 
109 

4 
8 
15 
23 
32 
41 
50 
58 
65 
71 
81 
90 
97 
103 
109 

6 
19 
27 
34 
40 
46 
52 
58 
64 
69 
79 
88 
96 
101 
105 

9 
18 
25 
30 
35 
40 
44 
49 
53 
57 
65 
73 
80 
88 
95 

20                   .  .  .  . 

30 

40  

50 

60  

70 

80  

90 

100 

120  

140 

160  

180 

200  

This  explains  why  the  trees  in  the  Cumberland  Mountains  and  in 
the  Mississippi  Valley,  in  spite  of  better  soil  conditions,  show  a  slower 
growth.  The  figures  given  for  the  Cumberland  Mountains  and  the 
Mississippi  Valley  are  from  trees  in  the  virgin  forest ;  those  for  the  Ohio 
Valley  and  for  northern  Ohio  are  from  second-growth  trees.  Under 
forest  management  the  growth  of  trees  in  these  regions  should  be 
faster  than  in  the  Ohio  Valley  and  in  northern  Ohio. 

Coppice  hickory  of  merchantable  size  is  scarce.  Table  6  is  based 
on  measurements  of  16  pignuts  and  6  shagbarks  growing  in  rather  dry 
situations,  on  red  clay  soil,  both  near  Bardstown,  Ky.,  and  Paoli,  Ind. 
Under  more  favorable  conditions  the  growth  should  be  considerably 
faster. 

TABLE  6. — Height  and  diameter  growth  of  pignut  and  shagbark  coppice. 


Age. 

Pignut. 

Shagbark. 

Diameter. 

Height. 

Diameter. 

Height. 

Years: 
10 

Inches. 
2.0 
3.8 
5.5 
7.0 
8.5 

Feet. 
18 
31 
43 
52 
59 

Inches. 
2.4 
4.4 
6.3 
7.4 
8.6 

Feet. 
13 
26 
38 
46 
54 

20  

30 

40... 

50  

32  THE   COMMERCIAL  HICKORIES. 

LENGTH    OF   LIFE. 

The  hickories  are  long-lived  trees,  though  not  as  long-lived  as  oaks. 
Pecan  probably  reaches  the  greatest  age.  A  tree  on  the  St.  Francis 
River  in  Arkansas  was  382  years  old,  146  feet  high,  and  48  inches  in 
diameter.  The  section  of  big  shellbark  in  the  Morris  K.  Jesup  collec- 
tion in  the  American  Museum  of  Natural  History  in  New  York  shows 
340  annual  rings.  The  oldest  shagbark  and  the  oldest  pignut  found 
grew  in  West  Virginia  and  were  each  350  years  old.  Mockernut  is 
apparently  shorter  lived.  Several  trees,  however,  in  the  Mississippi 
Valley  were  over  260  years  old.  Water  hickory,  nutmeg  hickory,  and 
particularly  bitternut,  are  even  shorter  lived  than  the  mockernut. 
Mature  trees  of  shagbark  and  pignut  are  usually  from  200  to  300  years 
old  and  grow  in  the  virgin  forest'  along  with  white  oak  and  other  long- 
lived  species. 

SUSCEPTIBILITY    TO    INJURIES. 

Though  comparatively  free  from  serious  dangers  and  diseases, 
hickory,  in  common  with  all  other  trees,  is  subject  to  various  injuries. 

A  serious  injury  from  the  commercial  standpoint,  though  of  little 
danger  to  the  life  of  the  tree,  is  what  is  known  as  "birdpeck."  This 
is  a  discoloration  of  the  wood  caused  chiefly  by  the  work  of  the  sap- 
sucker,  which,  especially  in  the  spring,  drills  into  the  cambium  of  the 
tree  after  the  sap.  The  hole  cuts  off  the  flow  of  sap,  and  a  black 
streak  from  one-eighth  to  three-eighths  inch  wide  extends  a  foot  or 
so  above  and  below  the  wound  along  the  line  of  the  pores  affected. 
This  streak  probably  does  not  affect  seriously  the  strength  or  tough- 
ness of  the  wood,  but  it  does  affect  the  appearance,  and  the  prejudice 
against  " streaky  hickory"  is  very  strong. 

Birdpecks  are  most  prevalent  in  trees  on  south  slopes  and  in  situ- 
ations where  the  sap  will  flow  most  quickly  on  warm  winter  days  or 
in  the  early  spring.  The  damage  is  very  extensive,  and  an  immense 
amount  of  wood — perhaps  as  much  as  10  per  cent  of  the  merchantable 
material — is  left  in  the  woods  on  account  of  birdpeck. 

The  living  hickory  trees  support  a  large  number  of  different  kinds 
of  insects,  some  feeding  on  the  leaves,  others  on  the  nuts,  and  still 
others  on  the  bark  and  wood  of  the  twigs,  branches,  and  trunks,  but 
there  is  only  one  species  responsible  for  any  extensive  dying  of  the 
trees.  This  is  the  hickory  barkbeetle  (Scolytus  quadrispinosus) 
which,  during  the  past  ten  years,  has  been  directly  responsible  for  the 
death  of  so  much  of  the  best  hickory  timber  throughout  the  area  in 
which  the  hickory  grows,  but  especially  in  the  northern  section  of  its 
distribution,  from  Connecticut  to  Wisconsin.  Wood  of  the  living 
trees,  especially  of  the  younger  ones,  is  injured  to  some  extent  by 
wood-boring  grubs  or  larvre  of  several  species  of  long-horned  beetles 
of  the  genus  Goes.  The  wood  of  dying  and  dead  trees,  and  of  saw- 
logs,  handles,  poles,  and  other  unseasoned  products  with  the  bark  on, 


Bui.  80,  Forest  Service,  U.  S.  Dept.  of  Agriculture. 


PLATE  IV. 


CO 

OH 

II 


•33 

.*§ 

CO 

O 


^jMNMiM^  •'  • ''  <  *a*"IM 

•*  >-^»'  V' rv^f  ^*^* ••"*  "  **w*««»* «r2r-  '•  .*•      s 


VOLUME   AND   YIELD.  33 

is  often  seriously  damaged -by  various  kinds  of  wood-boring  beetles 
and  larva?.  The  sapwood  of  all  kinds  of  hickory  wood  products,  even 
after  seasoning,  is  subject  to  great  damage  by  various  species  of 
powder  post  insects.  In  short,  insect  injury  has  contributed  greatly 
to  waste  in  hickory,  and  has  reduced  revenues  and  profits.  Practical 
methods  of  preventing  losses  from  these  insects  have  been  determined 
and  may  be  adopted  and  successfully  carried  out  at  slight  expense.0 

A  very  serious  defect  of  hickory  trees  is  "  cup-shake."  This  occurs 
commonly  in  the  heartwood  of  mature  trees  in  those  portions  where 
the  growth  has  been  very  slow,  and  consequently  a  number  of  open 
porous  layers  come  together.  It  is  most  common  where  the  porosity 
of  the  wood  is  increased  by  a  large  amount  of  moisture  in  the  soil, 
and  therefore  most  likely  to  occur  in  southern  hickory.  There  are 
two  ways  by  which  loss  from  this  source  can  be  entirely  avoided, 
first,  by  keeping  the  trees  growing  steadily,  so  that  no  succession  of 
narrow  rings  will  be  formed,  and,  second,  by  cutting  them  before  they 
reach  large  size. 

Young  hickories  are  very  susceptible  to  frost.  Out  in  the  open, 
without  protection  from  an  older  stand,  they  are  apt  to  be  killed  back 
by  frost,  and  this  forms  one  of  the  chief  objections  to  growing  hickory 
in  plantations  in  the  northern  part  of  its  range;  it  has  proved  an 
obstacle  to  the  introduction  of  the  hickories  into  Germany,  where  big 
shellbark  and  mockernut  are  too  sensitive  to  grow  successfully. 
Bitternut,  pignut,  and  shagbark  are  unquestionably  the  least  sus- 
ceptible to  frost  and  pecan  and  water  hickory  the  most. 

A  source  of  considerable  injury  in  some  places  is  the  practice  of 
bumping  or  striking  against  the  trunks  of  young  shagbarks  or  big 
shellbarks  with  a  heavy  object  or  a  long  pole  to  shake  down  the  nuts 
in  the  fall.  It  causes  serious  defects,  if  not  actual  decay  in  the  wood. 

VOLUME  AND  YIELD. 
VOLUME. 

One  of  the  first  things  which  a  practical  lumberman  wants  to  know 
about  a  tree  is  how  much  merchantable  lumber  it  contains  and  what 
is  its  quality ;  he  usually  answers  this  by  estimating  the  product  which 
may  be  obtained  from  it.  By  long  years  of  experience  he  becomes 
very  skillful  in  thus  determining  the  contents  of  a  tree.  In  buying  and 
selling  stumpage  it  is  essential  to  determine  the  volume  of  single  trees, 
for  by  the  estimates  of  individual  trees  the  value  of  the  stand  is 
determined. 

To  determine  the  value  of  a  particular  tree,  the  most  satisfactory 
method  is  to  estimate  the  number  and  size  of  the  logs  which  it  con- 

«For  specific  information  about  the  insects  injurious  to  hickory  or  other  forest 
trees,  inquiries  should  be  made  directly  to  the  Bureau  of  Entomology,  U.  S.  Depart- 
ment of  Agriculture,  and,  whenever  possible,  specimens  of  the  insects  and  of  their 
work  should  be  submitted. 


34  THE   COMMERCIAL   HICKORIES. 

tains.  This  is  particularly  true  in  the  case  of  hickory,  in  which  free- 
dom from  knots  and  birdpecks,  rapidity  of  growth,  and  width  of 
sapwood  are  so  important,  and  vary  so  greatly  under  different  con- 
ditions. In  an  open  stand,  for  instance,  the  trees  run  knottier  and 
there  is  less  merchantable  length,  but  the  growth  is  more  rapid  and  the 
quality  of  the  wood  is  better.  In  poor  or  exposed  situations  the 
growth  is  slow  and  the  wood  is  apt  to  be  birdpecked.  Lumbering, 
moreover,  differs  greatly  with  the  region  and  the  purpose  of  cutting. 
A  great  deal  more  of  the  tree  is  used,  for  instance,  when  it  is  cut  for 
handles  than  when  it  is  cut  for  rims  or  shafts,  and  utilization  is  much 
closer  in  the  North  and  East  than  it  is  in  the  Mississippi  Valley. 

Nevertheless,  it  is  important,  also,  to  know  how  much  wood  average 
trees  of  different  sizes  contain  and  how  much  is  merchantable.  The 
average  tree  can  be  used  in  estimating,  and,  when  applied  to  a  large 
number  of  trees,  gives  fairly  satisfactory  results.  It  is  especially 
valuable  in  predicting  future  yields  and  can  be  used  to  foretell  the 
increase  in  volume  of  a  10  or  12  inch  tree  after  it  has  made  a  certain 
definite  increase  in  diameter. 

While  the  merchantable  volume  of  two  hickory  trees  of  the  same 
diameter  and  height  may  differ  greatly,  there  is  apt  to  be  a  greater 
difference  between  a  hickory  and  an  oak  or  an  ash  of  similar  dimen- 
sions. Each  species  has  its  own  characteristic  form  and  its  own  special 
uses.  It  is  therefore  desirable  to  determine  the  contents  of  the  aver- 
age trees  of  each  species.  For  this  purpose  a  large  number  of  trees 
of  different  sizes  were  measured  and,  in  the  case  of  this  hickory  study, 
not  only  were  their  merchantable  volumes  determined,  but  the  amount 
of  firewood  contained  in  the  tops.  The  amount  of  heart,  sap,  and 
bark  in  the  used  portions  and  the  form  of  the  entire  stem  were  also 
measured. 

Table  7  shows  the  total  cubic  contents  including  bark  and  limbs  for 
trees  from  40  to  90  feet  high  and  5  to  18  inches  in  diameter,  breast- 
high.  The  average  used  volume  is  given  in  per  cent  of  the  total 
volume.  The  table  is  based  upon  the  measurements  of  365  trees  of 
five  different  species  of  hickory  cut  in  different  parts  of  the  country 
for  spokes,  handles,  rims,  and  shafts.  In  the  merchantable  portions, 
the  diameters  were  taken  to  tenths  of  inches ;  in  firewood,  only  4-foot 
sections,  2  inches  and  over  at  the  small  end,  were  considered,  and  the 
diameters  were  measured  in  the  middle  of  the  sticks  and  rounded  off 
to  half  inches.  The  volumes  are  given  in  cubic  feet,  since  this  is  the 
most  accurate  unit  of  measure  for  timber  of  different  classes.  To 
convert  cubic  feet  into  board  feet  it  may  be  considered  that  1  cubic 
foot  of  merchantable  material  will  saw  from  5  to  7  board  feet,  or,  on 
an  average,  6  board  feet.  To  convert  cubic  feet  into  cords,  it  may 
be  assumed  that  95  cubic  feet  of  spoke  or  handle  bolts  is  equal  to  1 
stacked  cord ;  and  that  1  cord  of  firewood  would  contain  from  60  to 
90  cubic  feet,  depending  on  the  size  and  straightness  of  the  sticks; 


VOLUME   AND   YIELD. 


35 


with  an  average  of  80  cubic  feet.  This  table  is  of  value  in  estimating 
future  yields  and  in  estimating  firewood  in  the  thickly  settled  regions 
of  the  North  where  hickory  is  closely  utilized.  It  may  be  used  for  esti- 
mating, though  with  caution,  since  it  represents  so  many  different 
regions  and  conditions  that  it  is  not  strictly  applicable  to  specific 


•'to 

cases. 


TABLE  7. —  Total  cubic  contents  of  hickories  and  proportion  of  used  volume. 


Diameter  breast-high—inches. 

Height—  feet. 

Used  vol- 
ume — 
per  cent. 

40. 

50. 

60. 

70. 

80. 

90. 

Total  volume  —  cubic  feet. 

5                                             

2.1 
3.3 

3.1 
4.5 
6.2 
8.2 
10.4 
13.0 
15.9 
19.0 
22.6 

4.3 
5.9 

7.9 
10.1 
12.8 
15.8 
19.3 
23.2 
27.5 
32.0 
36.8 

6.0 
7.8 
9.9 
12.5 
15.5 
19.0 
23.0 
27.4 
32.1 
37.2 
42.6 
48.4 
54.5 
60.8 

40 
41 
42 
44 
45 
47 
49 
50 
52 
53 
53 
54 
54 
54 

c, 

7 

4.7 
6.4 
8.2 
10.4 
12.8 
15.6 

12.6 
15.5 
18.8 
22.6 
27.0 
31.9 
37.2 
43.0 
49.1 
55.5 
62.5 
69.8 

g 

18.7 
22.5 
26.7 
31.5 
36.8 
42.8 
49.2 
55.8 
62.8 
70.4 
78.8 

»:::            :>::: 

10 

11      

12 

13 

14                                                                   

15 

16                                                   

17 

18 

Table  8  gives  cubic  contents  according  to  diameter  and  merchant- 
able length.  It  is  based  upon  the  measurements  of  630  trees.  By 
its  use  the  total  contents  of  a  tree  may  be  estimated  without  reference 
to  the  individual  logs. 

TABLE  8. — Cubic  contents  of  hickory  according  to  diameter  and  merchantable  length. 


Diameter 
breast- 
high- 
inches. 

Merchantable  length—  feet. 

Diam- 
eter 
inside 
bark  of 
top- 
inches. 

5. 

10. 

15. 

20. 

25. 

30. 

35. 

40. 

45. 

50. 

55. 

60. 

65. 

Volume—  cubic  feet. 

5 

1.0 
1.3 
1.6 
2.0 
2.5 
3.0 
3.5 
4.1 
4.8 
5.5 
6.2 
7.0 
8.0 

1.8 
2.5 
3.2 
4.0 
4.8 
5.8 
6.9 
8.0 
9.3 
10.5 
12.0 
14.0 
15.5 
17.5 
19.5 
21.5 
24.0 
26.0 
28.5 
31.0 
34.0 
36.5 

2.3 
3.2 
4.2 
5.4 
6.6 
8.1 
9.7 
11.5 
13.5 
15.5 
17.5 
20.0 
23.0 
25.5 
28.5 
32.0 
35.0 
38.0 
42.0 
45.0 
49.0 
53.0 
57.0 
61.0 

4 
5 
6 
6 
7 
8 
8 
9 
10 
11 
11 
12 
13 
14 
14 
15 
16 
16 
17 
18 
19 
19 
20 
20 

G 

3.6 
5.0 
6.5 
8.2 
10.0 
12.0 
14.5 
17.0 
20.0 
23.0 
26.5 
29.5 
33.0 
37.0 
41.0 
45.0 
50.0 
54.0 
59.0 
64.0 

74.  0 
80.0 

7... 
8  
9  
10 

5.7 
7.5 
9.6 
11.5 
14.0 
17.0 
20.5 
24.0 
27.5 
31.0 
36.0 
40.0 
45.0 
50.0 
54.0 
60.0 
65.0 
70.0 
76.0 
82.0 
89.0 
97.0 

10.0 
13.0 
16.0 
20.0 
23.5 
27.5 
32.0 
36.0 
41.0 
46.0 
52.0 
57.0 
63.0 
69.0 
75.0 
81.0 
88.0 
95.0 
103.  0 
112.0 

11  
12  

13 

18.0 
21.5 
26.0 
31.0 
36.0 
41.0 
46.0 
52.0 
58.0 
64.0 
71.0 
77.0 
84.0 
91.0 
99.0 
107.0 
IKi.O 
125.0 

23.5 
28.5 
34.0 
39.0 
45.0 
51.0 
58.0 
64.0 
71.0 
79.0 
86.0 
93.0 
102.0 
110.0 
119.0 
12S.  0 
137.0 

31 
37 
43 
50 
56 
63 
70 
78 
86 
94 
102 
111 
121 
130 
140 
.149 

14.   . 
15  

16  
17 

54 
61 
69 
76 
84 
93 
102 
111 
121 
130 
140 
151 
161 

66 
74 
82 
90 
100 
110 
120 
130 
140 
151 
162 
173 

18  
19 

20... 

97 
107 
118 
128 
139 
149 
161 
173 
185 

103 
113 
126 
137 
148 
158 
171 
183 
197 

21 

22... 

23 

24 

25  

26 

27  

28 

36 


THE   COMMERCIAL   HICKORIES. 


Table  9,  based  on  630  trees,  shows,  according  to  diameters,  the 
general  average  total  height  and  merchantable  length.  In  cases 
where  diameters  alone  are  known,  the  table  may  be  used  with  caution 
to  supply  the  missing  merchantable  lengths. 

TABLE  9. — Relation  between  height  and  merchantable  length  of  hickories  of  various 

diameters. 


Diameter  breast-high. 

Height. 

Average 
merchant- 
able 
length. 

Diameter  breast-high. 

Height. 

Average 
merchant- 
able 
length. 

Inches: 
5 

Feet. 
37 

Feet. 
6 

Inches: 
21 

Feet. 
112 

Feet. 
32 

6  

43 

8 

22 

115 

33 

7 

50 

10 

23 

117 

35 

8  

56 

12 

24  

119 

36 

9 

61 

14 

25 

121 

37 

10  

67 

16 

26  

122 

39 

11 

72 

17 

27 

124 

40 

12... 

77 

19 

28     

125 

42 

13 

82 

20 

29 

126 

43 

14 

86 

22 

30 

127 

44 

15  

91 

23 

31 

128 

46 

16 

95 

25 

32 

129 

47 

17  

99 

26 

33 

130 

49 

18 

102 

28 

34 

131 

50 

19  

106 

29 

35 

132 

51 

20 

109 

30 

36 

132 

52 

Table  10,  based  on  600  trees,  shows  the  proportion  of  heartwood, 
sapwood,  and  bark  in  the  merchantable  portions  of  trees  of  .different 
diameters.  It  may  be  used  in  connection  with  Table  8  to  show  how 
much  must  be  allowed  for  bark  and  what  proportion  of  the  cut  is 
sapwood. 

TABLE  10. — Proportion  of  heartwood,  sapwood,  and  baric  in  hickories  of  different  diameters. 


Diameter  breast- 
high. 

Heart- 
wood. 

Sapwood. 

Bark. 

Diameter  breast- 
high. 

Heart- 
wood. 

Sapwood. 

Bark. 

Inches: 
5  

Per  cent. 
3 

Per  cent. 
75 

Per  cent. 
22 

Inches: 
21           .     . 

Per  cent. 
42 

Per  cent. 
43 

Per  cent. 
15 

6 

6 

73 

21 

22 

43 

42 

15 

7  

9 

71 

20 

23 

45 

40 

15 

8 

13 

68 

19 

24 

47 

39 

14 

9  

15 

66 

19 

25  

48 

38 

14 

10 

18 

64 

18 

26 

49 

37 

14 

11... 

20 

62 

18 

27  

50 

36 

14 

12 

23 

60 

17 

28 

50 

36 

14 

13... 

25 

58 

17 

29  

51 

35 

14 

14 

28 

56 

16 

30 

52 

35 

13 

15... 

30 

54 

16 

31... 

52 

35 

13 

16  

17 

32 
34 

52 
50 

16 

16 

32  
33 

53 
53 

34 
34 

13 
13 

18  

37 

48 

15 

34 

54 

33 

13 

19 

39 

46 

15 

35 

54 

33 

13 

20  

40 

45 

15 

36. 

55 

33 

12 

Table  11  shows  the  proportion  of  heartwood,  sapwood,  and  bark 
in  the  merchantable  portions  of  the  stem  for  pignut,  shagbark,  and 
bitternut  in  the  Ohio  Valley.  This  table  shows  the  striking  contrast 
between  the  proportion  of  sapwood  produced  by  pignut  and  by  the 
other  two  species. 


VOLUME   AND   YIELD. 


37 


TABLE  11. — Proportion  of  heartwood,  sapwood,  and  bark;   second  growth,  Ohio  Valley. 


Diameter  breast-high. 

Pignut. 

Shagbark. 

Bitternut. 

Heart- 
wood. 

Sap- 
wood. 

Bark. 

Heart- 
wood. 

Sap- 
wood. 

Bark. 

Heart- 
wood. 

Sap- 
wood. 

Bark. 

Inches: 
5 

P  ct 

P  ct 

P.ct 

P  ct 

P  ct 

P  ct 

P*  ct 

P  ct 

P  ct 

0.0 
2.0 
4.0 
6.0 
8.0 
10.5 
13  0 

78.0 
76.5 
75.0 
73.5 
72.0 
70.0 
68.0 
66.0 
64.0 
61.5 
59.0 
56.5 

22.0 
21.5 
21.0 
20.5 
20.0 
19.5 
19.0 
18.5 
18.0 
18/0 
17.5 
17.0 

0.0 
3.5 

7.0 
11.0 
15.0 
19.0 
23.0 
27.0 
31.0 
35.0 
39.0 
46.0 

80.0 
77.0 
74.0 
70.5 
67.0 
63.0 
59.5 
56.0 
52.5 
49.0 
45.5 
39.0 

20.0 
19.5 
19.0 
18.5 
18.0 
18.0 
17.5 
-17.0 
16.5 
16.0 
15.5 
15.0 

17.0 
22.0 
27.0 
31.0 
36.0 
40.5 
44.5 
49.0 
52.5 
55.5 
58.0 
60.5 

66.0 
61.5 
57.0 
53.0 
48.5 
44.1 
40.0 
36.5 
33.5 
30.5 
28.0 
26.0 

17.0 
16.5 
16.0 
16.0 
15.5 
15.5 
15.0 
14.5 
14.5 
14.0 
14.0 
13.5 

6         .            

7 

8  

9                               

10 

11 

12 

15.5 
18.0 
20.5 
23.5 
26.5 

13                          

14 

15                  

16... 

The  form  of  the  stem  is  shown  in  Table  12,  based  on  the  measure- 
ments of  630  trees.  Although  the  form  varies  somewhat  with  dif- 
ferent species  and  again  with  different  regions,  the  table  makes  it 
possible  to  comparp  the  general  form  of  the  hickories  with  that  of 
other  trees;  this  comparison  brings  out  its  extremely  slender,  slightly 
tapering  stem.  The  practical  value  of  the  table  is  to  supply  missing 
measurements.  Thus  if  the  diameter  breast-high  alone  were  known, 
the  diameter  15  or  20  feet  above  the  ground  could  be  estimated  with 
some  degree  of  accuracy,  or  the  diameter  breast-high  could  be  deter- 
mined from  that  of  the  stump. 

TA BLE  12 . —  Taper  of  stem  of  hickories . 


Diameter  breast-high- 
inches. 


Height— feet. 


5. 


JO. 


20. 


40. 


Diameter  outside  bark — inches. 


1 

2.7 

2.0 

1.5 

1.1 

0.9 

0.2 

2  

3.8 

3.1 

2.5 

2.1 

1.9 

1.2 

3 

4.9 

4.2 

3.6 

3.1 

2.9 

2.2 

0.8 

4  

6.0 

5.2 

4.6 

4.2 

3.9 

3.1 

2.0 

0.1 

5  

7.1 

6.3 

5.6 

5.2 

4.9 

4.3 

3.2 

1.5 

6 

8.2 

7.4 

6.7 

6.2 

5.9 

5.4 

4.3 

2.9 

0  9 

7  

9.3 

8.4 

7.7 

7.2 

6.9 

6.3 

5.3 

4.0 

2.1 

8 

10.4 

9.4 

8.7 

8.2 

7.9 

7.3 

6.2 

5.0 

3  2 

9  

11.5 

10.5 

9.7 

•  9.2 

8.9 

8.2 

7.2 

6.0 

4.3 

10 

12.5 

11.6 

10.7 

10.2 

9.9 

9.1 

8.1 

6.9 

5.4 

11  

13.7 

12.6 

11.8 

11.2 

10.8 

10.1 

9.0 

7.9 

6.5 

12 

14.9 

13.6 

12.7 

12.2 

11.9 

11.0 

10.0 

8.9 

7.5 

13 

15  9 

14  8 

13  8 

13  2 

12  9 

12  0 

10  9 

9  9 

8  7 

14. 

17.1 

15.7 

14.8 

14.2 

13.8 

12.9 

11.9 

10.9 

9.8 

15 

18  1 

16  8 

15  9 

15  3 

14.8 

13  9 

12  8 

11  8 

10  7 

16... 

19.2 

17.8 

16.9 

16.3 

15.8 

14.8 

13.7 

12.8 

11.8 

17 

20  4 

19  0 

18.0 

17.3 

16.8 

15  7 

14.7 

13  8 

12  9 

18  

21.4 

20.1 

19.1 

18.3 

17.8 

16.6 

15.6 

14.8 

13.9 

19. 

22  5 

21.2 

20.1 

19.3 

18.7 

17.6 

16.5 

15  7 

14  8 

20 

23  7 

22  1 

21  0 

20  3 

19  7 

18  5 

17  5 

16  7 

15  8 

21  

24.7 

23.1 

22.0 

21.3 

20.7 

19.5 

18.4 

17.7 

16.8 

22 

25  9 

24  2 

23  0 

22  5 

21  8 

20  4 

19  3 

18  6 

17  7 

23  

27.0 

25.3 

24.1 

23.3 

22.7 

21.4 

20.2 

19.5 

18.6 

24 

28  0 

26  3 

25.2 

24.3 

23  7 

22  4 

21  0 

20  3 

19  4 

25  

29.2 

27.4 

26.1 

25.3 

24.7 

23.3 

21.8 

21.1 

20.2 

26 

30.4 

28.4 

27.1 

26.3 

25.7 

24  3 

22  7 

21  7 

20  8 

27 

31  6 

29  4 

28  1 

27  3 

26  7 

25  3 

23  5 

22  5 

21  6 

28  

32.6 

30.4 

29.2 

28.3 

27.8 

26.2 

24  2 

23  2 

22  3 

29 

33  7 

31  6 

30  2 

29  3 

28  7 

27  2 

25  0 

23  9 

23  0 

30  

35.1 

32.7 

31.3 

30.4 

29.8 

28.1 

25.8 

24  6 

23.6 

31 

36  2 

33  9 

32  4 

31  4 

30  7 

29  0 

26  6 

25  2 

24  3 

32  

37.5 

35.0 

33.4 

32.4 

31.7 

29.9 

27.3 

25.8 

24.9 

33 

38  6 

36.1 

34.5 

33  4 

32  6 

30  7 

28  1 

26  5 

25  5 

34  

39.8 

37.2 

35.5 

34.4 

33.7 

31.6 

28.8 

27.2 

26.2 

35 

41.2 

38.5 

36.7 

35.4 

34.6 

32  4 

29  5 

27.8 

26.8 

36  

42.5 

39.8 

37.9 

36.4 

35.7 

33.4 

30.3 

28.4 

27.4 

38 


THE   COMMERCIAL   HICKORIES. 
TABLE  12. —  Taper  of  stem  of  hickories — Continued. 


Diameter  breast-high- 
inches. 

Height—  feet. 

50. 

60. 

70. 

80. 

90. 

100. 

110. 

120. 

130. 

Diameter  outside  bark—  inches. 

I... 

2  . 

3  

4  

5 

6  

7 

8  

1.2 

9 

2.4 

0.3 

10 

3  5 

1  5 

11   . 

4.7 
5.9 
7.1 
8.3 
9.4 
10.5 
11.6 
12.7 
13.7 
14.7 
15.7 
16.6 
17.4 
18.2 
19.1 
19.8 
20.5 
2L3 
22.0 
22.6 
23.3 
23.9 
24.5 
25.1 
25.7 
26.4 

2.7 
3.9 
5.1 
6.3 
7.5 
8.8 
9.9 
10.9 
12.1 
13.0 
14.1 
15.0 
15.9 
16.8 
17.6 
18.4 
19.1 
19.9 
20.6 
21.3 
22.0 
22.7 
23.2 
23.8 
24.4 
25.1 

0.4 
1.6 
2.9 
4.1 
5.4 
6.6 
7.8 
9.0 
10.1 
11.1 
12.1 
13.1 
14.0 
14.9 
15.7 
16.5 
17.3 
18.0 
18.8 
19.5 
20.3 
21.0 
21.6 
22.2 
22.8 
23.5 

12 

13  

0.4 
1.6 
2.9 
4.1 
5.3 
6.5 
7.6 
8.7 
9.8 
10.8 
11.7 
.  12.6 
13.5 
14.3 
15.0 
15.8 
16.5 
17.2 
18.0 
18.7 
19.4 
20.1 
20.6 
21.3 

14 

15  

0.2 
1.4 
2.6 
3.8 
4.8 
5.8 
6.9 
8.0 
8.9 
9.7 
10.6 
11.5 
12.3 
13.1 
13.9 
14.6 
15.3 
15.9 
16.6 
17.2 
17.8 
18.4 

16 

17  

18.. 

0.8 
1.8 
2.8 
3.8 
4.9 
5.8 
6.5 
7.4 
8.3 
9.2 
9.9 
10.8 
11.4 
12.1 
12.6 
13.3 
13.9 
14.4 
14.9 

19 

20...    . 

21 

0.5 
1.6 
2.4 
3.1 
3.9 
4.7 
5.6 
6.3 
7.0 
7.7 
8.3 
8.8 
9.3 
10.0 
10.4 
10.9 

22  

23 

24  

25 

0.3 
1.0 
1.6 
2.3 
2.8 
3.4 
3.9 
4.4 
4.9 
5.4 
5.9 
6.3 

26  



27..      . 

28 

29  



30 

31  

32 

33  

0.1 
.5 
.9 
1.3 

34 

35  

36. 

Table  13  shows  contents,  in  cubic  feet,  of  logs  of  different  lengths 
by  diameters  at  the  small  end.  It  is  based  upon  the  taper  measure- 
ments given  in  Table  12.  It  is  an  accurate  log  rule  and  can  be  used 
equally  well  in  buying  and  selling  large  and  small  logs,  and  spoke 
and  handle  or  pole  and  shaft  or  sucker-rod  material.  The  Forest 
Service  in  Bulletin  36,  "The  Woodsman's  Handbook,"  recommends 
that  all  log  rules  should  be  standardized  by  computations  based 
on  the  diameter  at  the  middle  of  the  log.  In  the  case  of  hickory, 
however,  the  rule  based  on  diameters  at  the  small  end  has  some 
advantages. 


VOLUME   AND   YIELD. 
TABLE  13. — Log  rule  for  hickory,  giving  contents  in  cubic  feet. 


39 


Diameter  at  small 
end  of  log—  inches. 

Length  of  log—  feet. 

2. 

2.5. 

3. 

3.5. 

4. 

5. 

6. 

7. 

8. 

9. 

Volume  o-  -cubic  feet. 

4 

0.2 
.3 
.4 
.6 
.7 
.9 
1.1 
1.3 
1.6 
1.9 
2.2 
2.5 
2.8 
3.2 
3.6 
4.0 
4.4 
4.9 
5.3 
5.8 
6.3 

0.2 
.4 
.5 
.7 
.9 
1.2 
1.4 
1.7 
2.0 
2.4 
2.8 
3.2 
3.6 
4.0 
4.5 
5.0 
5.6 
6.1 
6.7 
"   7.3 
8.0 

0.3 
.4 
.6 
.9 
1.1 
1.4 
1.7 
2.1 
2.4 
2.9 
3.3 
3.8 
4.3 
4.8 
5.4 
6.0 
6.7 
7.4 
8.1 
8.8 
9.6 

0.4 
.5 
.8 
1.0 
1.3 
1.7 
2.0- 
2.4 
2.9 
3.4 
3.9 
4.5 
5.1 
5.7 
6.4 
7.1 
7.9 
8.7 
9.5 
10.4 
11.3 

0.4 
.6 
.9 
1.2 
1.5 
1.9 
2.3 
2.8 
3.3 
3.9 
4.5 
5.1 
5.8 
6.5 
7.3 
8.1 
9.0 
9.9 
10.9 
11.8 
12.9 

0.5 
.8 
1.1 
1.5 
1.9 
2.4 
3.0 
3.6 
4.2 
4.9 
5.7 
6.5 
7.3 
8.3 
9.2 
10.3 
11.4 
12.5 
13.7 
14.9 
16.2 

0.6 
1.0 
1.3 
1.8 
2.3 
2.9 
3.5 
4.3 
5.0 
5.9 
6.8 
7.8 
8.8 
9.9 
11.1 
12.3 
13.6 
15.0 
16.4 
17.9 
19.5 

0.8 
^2 
1.6 
2.2 
2.8 
3.4 
4.2 
5.1 
6.0 
7.0 
8.0 
9.2 
10.4 
11.7 
13.1 
14.5 
16.0 
17.7 
19.3 
21.1 
22.9 

0.9 
1.4 
1.9 
2.5 
3.2 
4.0 
4.9 
5.9 
6.9 
8.1 
9.3 
10.6 
12.0 
13.5 
15.1 
16.8 
18.5 
20.4 
22.3 
24.3 
26.4 

1.0 
1.5 
2.1 
2.8 
3.6 
4.5 
5.5 
6.6 
7.8 
9.1 
10.5 
11.9 
13.5 
15.2 
17.0 
18.9 
20.8 
22.9 
25.1 
27.3 
29.7 

5.            

6 

8 

9  

10  
11  

12                   .   . 

13 

14  

15 

16  

17 

18        

19 

20  

21 

22  

23 

24  

Diameter  at  small 
end  of  log—  inches. 

Length  of  log  —  feet. 

10. 

11. 

12. 

13. 

14. 

15. 

16. 

17. 

18. 

Volume  a  —  cubic  feet. 

4 

1.2 

5  

1.8 
2.5 
3.2 
4.1 
5.1 
6.3 
7.5 
8.8 
10.2 
11.8 
13.4 
15.2 
17.1 
19.1 
21.2 
23.4 
25.7 
28.1 
30.6 
33.3 

2.0 
2.8 
3.7 
4.6 
5.8 
7.0 
8.4 
9.8 
11.4 
13.2 
15.0 
16.9 
19.0 
21.2 
23.5 
26.0 
28.5 
31.2 
34.0 
36.9 

2.2 
3.0 
4.0 
5.1 
6.3 
7.6 
9.1 
10.7 
12.5 
14.3 
16.3 
18.5 
20.7 
23.1 
25.7 
28.3 
31.1 
34.0 
37.1 
40.3 

2.5 
3.4 

4.4 
5.6 
7.0 
8.4 
10.0 
11.8 
13.7 
15.7 
17.9 
20.3 
22.7 
25.3 
28.1 
31.0 
34.0 
37.2 
40.5 
44.0 

2.7- 
3.7 
4.9 
6.2 
7.6 
9.2 
11.0 
12.9 
15.0 
17.2 
19.5 
22.1 
24.7 
27.6 
30.6 
33.7 
37.0 
40.4 
44.0 
47.7 

6 

4.0 
5.2 
6.6 
8.2 
9.9 
11.8 
13.8 
16.0 
18.4 
20.9 
23.6 
26.5 
29.5 
32.7 
36.1 
39.6 
43.3 
47.1 
51.1 

4.4 
5.7 
7.2 
8.9 
10.8 
12.8 
15.0 
17.3 
19.9 
22.6 
25.5 
28.6 
31.8 
35.3 
38.9 
42.6 
46.6 
50.7 
55.0 

4.8 
6.2 
7.9 
9.7 
11.6 
13.8 
16.2 
18.7 
21.4 
24.3 
27.4 
30.7 
34.2 
37.8 
41.7 
45.7 
49.9 
54.3 
58.9 

5.2 
6.8 
8.5 
10.4 
12.6 
14.9 
17.4 
20.1 
23.0 
26.1 
29.4 
32.9 
36.6 
40.5 
44.6 
48.8 
53.3 
58.0 
62.8 

7  

8  ..    . 

9 

10  

11 

12  

13 

14  

15 

16  

17 

18  

19 

20  

21 

22  

23 

24  

a  This  table  is  computed  on  an  average  taper  of  1  inch  in  7  feet,  used  length,  which  is  a  maximum  for 
small  trees,  but  very  conservative  for  medium  and  large  sized  trees.  In  computing  this  average  taper 
the  rapid  taper  below  the  5-foot  point  was  excluded. 


40 


THE   COMMERCIAL  HICKORIES. 


YIELD. 

Yield  tables  show  how  much  wood  a  given  species  will  produce  to 
the  acre  at  different  ages.  In  connection  with  tree  values,  these 
tables  enable  the  intelligent  woodlot  owner  to  tell  what  trees  it  will 
pay  him  best  to  grow.  Longleaf  pine,  for  instance,  produces  a 
stronger  and  more  valuable  wood  than  loblolly  pine  and  has  the 
additional  advantage  of  producing  resin  in  merchantable  quantities, 
but  it  is  slower  growing,  and  the  yield  per  acre  at  the  end  of  fifty  or 
eighty  or  one  hundred  years  is  less  than  that  from  loblolly.  Conse- 
quently he  regards  the  loblolly  as  the  better  tree,  and  on  soils  which 
are  suited  to  it  he  favors  it  over  the  longleaf.  Similarly,  conifers, 
such  as  pine,  spruce,  and  Douglas  fir,  are  a  more  profitable  crop  than 
broad-leaf  trees,  such  as  oak,  ash,  and  black  walnut,  because  their 
greater  yield  more  than  offsets  the  lower  value  of  the  wood.  The 
yield  per  acre  per  year,  under  similar  conditions  of  soil  and  climate 
and  in  stands  of  equal  age  and  density,  should  be  constant  for  a 
given  species  and  often  will  differ  greatly  from  that  of  other  species^ 
The  determination  of  yield  is  of  most  importance  for  trees,  such  as 
pine  and  spruce,  that  grow  naturally  in  pure,  even-aged  stands,  but 
even  in  the  case  of  hickories,  which  usually  grow  in  mixture  with 
other  species,  computations  of  yield  per  acre  offer  comparisons  with 
other  species  and  indicate  how  well  the  hickories  utilize  the  space 
which  they  occupy. 

In  computing  yields  it  is  necessary  to  know^not  only  the  size  of 
the  trees,  but  also  how  many  there  are  per  acre.  The  best  way  to 
determine  these  two  points  is  by  actual  measurement  of  pure,  even- 
aged  stands  of  different  ages.  Such  measurements  of  30  plots,  with 
an  average  area  of  one-fourth  acre,  in  several  regions  and  for  various 
species,  showed  the  average  yields  of  pure,  even-aged  stands  of 
hickory  at  different  ages  to  be  as  given  in  Table  14. 

TABLE  14. — Average  yield  of  hickory  per  acre. 


Age. 

Average 
diameter 
breast-high. 

Average 
height. 

Trees. 

Total 
volume. 

Merchant- 
able 
volume. 

Years: 
30 

Inches. 
4.0 

Feet. 
33 

Number. 
700 

Cubic  feet. 
800 

Cubic  feet. 
100 

40  

5.0 

41 

480 

1,100 

300 

50..    . 

6.  2 

49 

320 

1,400 

500 

60 

7.2 

57 

230 

1,700 

700 

70  

8.1 

64 

180 

2,000 

850 

80 

9.0 

69 

155 

2,300 

1,000 

90 

9  8 

74 

135 

2,600 

1,150 

100  

10.5 

78 

120 

2,900 

1,300 

120 

11  8 

85 

100 

3,500 

1,650 

150  

13.4 

92 

75 

4,400 

2,000 

200  

19.0 

100 

05 

5,700 

2,700 

It  will  be  noted,  first,  that  the  average  diameters,  except  during 
the  earlier  years,  fall  below  those  given  for  shagbark  and  pignut  in 
Table  4.  This  is  because  the  stands  in  many  cases  were  too  dense, 


THE    WOOD   AND   ITS    MECHANICAL   PROPERTIES.  41 

so  that  the  growth  had  become  very  slow.  Under  management 
which  should  aim  to  secure  rapid  growth  and  strong  wood  the  stands 
should  be  thinned,  and  thus  opened  up.  This  means  that  after  the 
fiftieth  year  there  would  be  fewer  trees  than  is  indicated  in  the  table, 
but  their  growth  would  be  hastened.  The  total  volume  increase  is 
300  cubic  feet  each  decade,  or  an  average  yield  of  30  cubic  feet  a 
year.  This  is  a  safe  estimate  for  fully  stocked  stands  on  soils  of 
moderate  fertility.  Two  sprout  stands  in  Ohio  22  and  45  years  old, 
on  very  good  soil,  showed  a  yield  of  44  cubic  feet  a  year,  while  three 
seedling  stands  200  years  old  on  river  bottoms  in  the  South  showed 
a  yield  of  36  cubic  feet  a  year.  The  minimum  yield  from  dry  situa- 
tions and  on  shallow  soils  was  15  cubic  feet.  There  was  no  difference 
discovered  in  the  yields  of  shagbark,  pignut,  and  mockernut. 

The  fact  that  the  heaviest  yields  were  produced  by  stands  of  sprout 
origin,  while  not  conclusive,  indicates  that  sprout  stands  may  be 
expected  to  produce  heavier  yields  than  seedling  stands  under  short 
rotations.  This  is  ot  great  importance  in  deciding  upon  the  method 
of  management. 

While  conclusive  figures  on  the  yield  of  the  important  American 
hard  woods  is  lacking,  there  are  enough  to  make  general  compari- 
sons possible.  Studies  made  by  the  Forest  Service  in  Illinois  show 
that  catalpa  makes  an  annual  average  growth  of  1.35  cords  per  acre; 
black  walnut,  0.90  cord;  ash,  0.89  cord;  and  osage  orange,  0.54 
cord;  in  Maryland  and  Virginia,  yellow  poplar,  1.1  cords;  and  in 
southern  New  England,  chestnut,  about  1  cord,  and  mixed  oak  and 
chestnut  sprouts  from  one-half  to  three-fourths  of  a  cord.  Catalpa, 
moreover,  is  ready  to  market  in  twenty  years,  and  chestnut  in  from 
thirty  to  sixty.  These  figures  are  rough  and  must  be  taken  with 
considerable  allowance,  but  even  with  due  allowance  the  comparison 
is  very  unfavorable  to  hickory,  because  the  other  important  commer- 
cial hard  woods  produce  more  merchantable  material  and  some  of 
them  mature  in  a  much  shorter  time. 

THE  WOOD  AND  ITS  MECHANICAL  PROPERTIES. 

The  technical  qualities  of  the  wood  are,  in  cases  of  the  hickories, 
of  first  importance.  It  is  to  its  toughness,  strength,  and  elasticity 
almost  entirely  that  the  hickory  owes  its  value.  It  is  therefore  im- 
portant to  know  to  what  extent  it  is  actually  superior  to  other  woods 
like  oak,  maple,  or  eucalyptus,  and  also  which  of  the  different  species 
are  most  valuable,  and  under  what  silvical  conditions  the  best  timber 
may  be  produced.  It  is  also  important  to  know  the  range  of  strength 
and  toughness  of  different  kinds  of  hickory,  so  as  to  be  able  to  dis- 
tinguish good  hickory  from  poor  hickory  by  its  physical  character- 
istics, and  to  know  from  what  parts  of  the  tree  the  best  wood  usually 
can  be  secured. 


42  THE   COMMERCIAL  HICKORIES. 

HICKORY    TESTS. 

To  answer  these  questions  a  series  of  tests  was  undertaken  at  the 
Forest  Service  laboratory  at  Purdue  University. 

DESCRIPTION    OP   MATERIAL. 

The  material  was  secured  from  4  different  localities  and  includes  7 
different  species. 

Hickory  from  the  South. — Thirty-three  trees  were  secured  from 
Sardis,  Miss.  Of  these,  4  trees  were  shagbarks,  4  pignuts,  8  mocker- 
nuts,  10  big  shellbarks,  10  nutmeg  hickories,  and  2  water  hickories. 

The  soil  conditions  were  typical  of  the  Mississippi  Delta  region. 
The  land  is  low  and  flat,  water  stands  in  pools  during  the  winter 
months,  and  the  ground  is  moist  or  wet  the  year  round ;  the  soil  is  a 
rich,  sandy  loam  underlain  by  clay.  The  forest  is  composed  chiefly 
of  cow  oak,  willow  oak,  red  gum,  elm,  ash,  and  shagbark,  pignut,  and 
mockernut  hickories.  Water  hickory  and  big  shellbark  are  more 
scattering  and  are  confined  to  the  moist  situations.  Mockernut  is  a 
small  tree  that  grows  on  dry  situations  and  does  not  figure  promi- 
nently in  the  southern  cut. 

The  trees  included  in  this  southern  shipment  were  comparatively 
large  and  overmature  and  typical  of  the  region.  They  were  mostly 
from  200  to  300  years  old  and  about  28  inches  in  diameter  and  from 
100  to  120  feet  in  height,  except  the  big  shellbarks,  which  averaged 
about  16  inches  in  diameter  and  about  95  feet  in  height.  Water  and 
nutmeg  hickories  are  common  enough  but  are  scarcely  cut  at  all  in 
the  South,  because  of  their  recognized  inferiority. 

Like  most  of  the  southern  hickory,  this  material  was  comparatively 
clear,  but  had  many  wormholes,  and  in  drying  became  shaky,  espe- 
cially the  nutmeg  and  water  hickories.  The  trees  were  cut  in  October 
and  shipped  in  November. 

Hickory  from,  Ohio. — Forty  trees  were  secured  near  Napoleon,  Ohio. 
Of  these,  10  were  shagbarks,  10  pignuts,  9  big  shellbarks,  and  11 
bitternuts. 

The  soil  conditions  here  are  typical  of  the  lake  region  of  northern 
Indiana  and  Ohio.  The  land  is  low,  flat,  and  poorly  drained,  with  a 
sandy  soil  underlain  by  clay ;  there  is  hardpan  at  a  depth  of  from  6  to  8 
feet.  This  land  must  be  drained  before  it  can  be  successfully  farmed. 
The  trees  in  mixture  were  elm,  white  ash,  white,  bur,  and  red  oaks, 
and  shagbark,  big  shellbark,  pignut,  and  bitternut  hickories. 

The  pignut  grew  on  the  better-drained  lands  and  the  bitternut  and 
big  shellbark  on  moist  ground.  The  shagbark  and  pignut  were 
typical  of  the  trees  being  cut  in  this  region  and  were  of  average 
quality,  with  ages  ranging  from  65  to  220  years.  The  diameter  at 


THE   WOOD  AND  ITS   MECHANICAL  PROPERTIES.  43 

breastheight  was  from  5  to  21  inches  and  the  total  height  from  60  to 
80  feet.  The  big  shellbarks  were  about  130  years  old,  11  inches  in 
diameter  breast-high,  and  60  feet  in  height,  and  would  all  be  classed 
as  the  finest  second  growth.  The  bitternuts  were  from  65  to  100 
years  old,  9  to  17  inches  in  diameter,  and  from  65  to  95  feet  high. 
They  were  all  young,  rapid-growing  trees  and  much  superior  in  this 
respect  to  the  shagbark  and  pignut. 

The  trees  were  cut  during  October  and  November  and  were  shipped 
December  1.  In  both  the  Mississippi  and  Ohio  shipments  each  tree 
was  selected  in  the  woods.  Its  diameter  and  height  were  measured, 
and  the  soil  and  other  conditions  were  carefully  described. 

Hickory  from  West  Virginia. — Thirty  trees  were  obtained  from  Holly, 
Webster  County,  W.  Va. — 10  shagbarks,  19  pignuts,  and  1  mocker- 
nut.  The  soil  conditions  here  are  typical  of  much  of  the  Southern 
Appalachians.  The  altitudes  are  from  900  to  1,800  feet  and  the 
slopes  very  steep.  The  hickories  cut  here  are  mostly  large,  over- 
mature trees  from  the  east  and  north  slopes,  where  they  grow  with 
white  oak,  yellow  poplar,  basswood,  buckeye,  maple,  and  red  and 
black  ash.  Of  this  shipment,  12  typical  trees — 7  shagbarks  and  5 
pignuts — were  selected  in  the  yard.  The  ages  were  from  100  to  350 
years,  the  diameters  from  14  to  24  inches.  Some  of  the  logs  were 
shaky,  but  not  so  much  so  as  in  the  southern  hickories. 

The  other  18  trees  were  cut  by  the  Forest  Service,  and  soil  and 
silvical  conditions  were  carefully  described  in  the  case  of  each  tree. 
Of  these  trees,  3  shagbarks  and  9  pignuts  represent  northern  and 
eastern  slopes.  The  trees  ranged  from  45  to  220  years  old,  9  to  16 
inches  in  diameter,  and  from  65  to  100  feet  high,  and  they  are  better 
than  most  of  the  hickory  which  is  being  cut  in  this  locality.  The 
material  from  these  trees  would  be  considered  strictly  second  growth. 
Five  pignuts  and  1  mockernut  came  from  a  dry,  steep,  rocky  slope 
where,  because  of  extremely  unfavorable  conditions  the  growth  is 
slow  and  stunted.  These  trees  were  from  140  to  230  years  old,  8  to 
10  inches  in  diameter,  and  from  50  to  60  feet  high. 

The  cutting  was  done  in  February  and  March,  and  the  material  was 
shipped  March  15,  1908. 

Hickory  from  Pennsylvania. — Thirty-nine  trees  were  obtained  in 
Chester  County,  Pa.  Of  these,  27  were  pignuts,  including  2  distinct 
varieties,  the  true  pignut  and  the  small-fruited  pignut,  11  were 
mockernuts,  and  1  was  shagbark.  The  soil  was  fresh,  sandy  loam, 
of  excellent  quality,  splendidly  suited  for  agriculture.  The  region 
is  a  long-settled  one  and  the  woodlots  have  been  culled  over  for  many 
years,  so  that  conditions  have  been  most  favorable  for  good  growth. 
The  trees  in  mixture  with  the  hickories  in  this  region  are  white,  red, 
and  black  oak,  chestnut,  and  white  ash. 


44  THE  COMMERCIAL  HICKORIES. 

Two  pignuts  and  6  mockernuts  came  from  eastern  Maryland  and 
were  selected  in  the  yard.  The  other  trees  were  obtained  from  4 
different  woodlots. 

The  material  is  typical  of  the  hickory  cut  in  this  locality.  In  age 
it  ranges  from  70  to  240  years,  but  most  of  the  trees  are  from  150  to 
200  years  old,  with  diameters  of  from  14  to  20  inches,  and  heights  of 
from  80  to  100  feet. 

The  cutting  was  done  in  March.  The  material  was  shipped  partly 
in  April  and  partly  in  May. 

CARE    OP   MATERIAL. 

From  each  of  these  trees  1  flitch  was  cut  through  the  center  of  the 
butt  log  from  bark  to  bark.  The  flitches  were  4  inches  thick  and 
from  7  to  12  feet  long,  depending  on  the  length  of  the  log.  From  a 
few  trees  flitches  were  secured  from  the  upper  logs,  and  the  entire 
merchantable  boles  of  two  pignuts  from  Pennsylvania  were  used  to 
determine  the  strength  as  affected  by  height  in  the  tree. 

Upon  arrival  at  the  laboratory  the  flitches  were  cut  into  sticks 
2J  by  2J  by  30  inches,  and  the  specimens  intended  for  green  tests 
were  immersed  in  water  until  the  time  of  test  to  preserve  them  in 
the  green  condition.  The  temperature  of  the  wood  at  the  time  of 
test  was  about  the  same  for  all  specimens,  so  that  the  relative  strength 
would  not  be  affected  by  this  cause.  Shortly  before  the  time  of  test 
the  specimens  were  removed  from  the  water,  planed  to  2  by  2  inches, 
and  sawed  to  a  uniform  length  of  28  inches  for  the  bending  test. 
After  the  bending  test  specimens  were  cut  from  the  uninjured  por- 
tion of  the  beam  for  other  tests. 

In  cutting  the  individual  test  pieces  from  the  flitches  no  attempt 
was  made  to  select  pieces  which  might  yield  the  highest  results. 
However,  specimens  were  selected  so  as  to  avoid  shakes  and  culls 
and  to  include  the  various  kinds  of  growth  found  in  any  given  flitch, 
and  specimens  that  contained  visible  defects  which  would  certainly 
lower  the  strength  were  not  included  in  the  tests. 

METHODS    OP   TEST.« 

The  specimens  were  all  accurately  measured  and  weighed,  the  per 
cent  of  sapwood  measured,  and  the  number  of  rings  per  inch  counted. 
The  nonporous  part  of  the  annual  rings  was  measured  and  its  pro- 
pro  tion  given  in  per  cent  of  the  whole  growth;  the  moisture  content 
was  determined  in  per  cent  of  oven-dry  weight. 

Static  bending  tests  are  the  most  important  of  the  tests  made. 

Beams  2  inches  square  and  28  inches  long  were  supported  on  knife 
edges  26  inches  apart.  Plates  and  rollers  were  used  to  avoid  crushing 

a  The  methods  of  test  were  those  described  in  Circular  38,  Forest  Service,  entitled 
"Instructions  to  Engineers  in  Timber  Tests." 


THE    WOOD   AND   ITS    MECHANICAL   PROPERTIES.  45 

the  specimen  and  to  do  away  with  any  friction  at  the  end  bearings. 
The  load  was  applied  at  the  center  by  a  screw  testing  machine.  The 
moving  head  of  the  machine  descended  at  a  uniform  speed  of  0.09  inch 
per  minute.  The  amount  of  bending  was  noted  for  each  100  pounds 
increase  in  load  up  to  the  point  where  the  stick  began  to  give  away, 
after  which  the  loads  were  read  for  each  0.1  inch  increase  in  deflection. 
The  load  bending  curve  was  platted  at  the  time  of  test,  and  the  load 
and  deflection  were  recorded  at  first  visible  failure  and  at  maximum 
load. 

The  following  points  were  determined :  Specific  gravity  as  tested  and 
oven  dry,  weight  per  cubic  foot  as  tested  and  oven  dry,  fiber  stress 
at  elastic  limit,  modulus  of  rupture,  modulus  of  elasticity,  horizontal 
shear  at  maximum  load,  work  or  resilience  to  elastic  limit,  work  to 
maximum  load,  and  total  work. 

Of  these,  the  most  important,  in  the  consideration  of  a  timber  like 
hickory,  are  the  strength  at  maximum  load,  as  shown  by  the  modulus 
of  rupture,  and  work  to  maximum  load. 

Strength  at  maximum  load  is  a  measure  of  the  ability  of  the  timber 
to  hold  a  load  applied  without  shock. 

Work  to  maximum  load  is  a  measure  of  the  ability  of  the  timber 
to  withstand  a  shock  or  blow  or  any  very  suddenly  applied  load. 
It  is  a  measure  of  toughness. 

Other  tests  were  also  made  in  compression  parallel  to  the  grain, 
compression  perpendicular  to  the  grain,  shear,  abrasion,  shrinkage, 
impact,  and  torsion. 

HICKORY    WOOD   AS    COMPARED    WITH    OTHERS. 

None  of  the  pines  or  other  conifers  compare  with  hickory  in  strength 
and  toughness. 

Of  the  broad-leaf  trees,  some  varieties  of  eucalyptus  have  about 
the  strength  of  good  hickory,  but  the  grain  is  locky  and  the  wood 
hard  to  work;  furthermore,  they  have  not  the  toughness  of  hickory, 
especially  in  the  small  sizes,  where  the  locky  grain  might  cause 
failure. 

Hard  maple  wagon  axles  are  more  nearly  comparable  to  hickory 
than  those  of  any  other  wood.  Hard  maple  has  about  the  strength 
of  hickory,  though  it  is  somewhat  inferior  in  toughness.  For  this 
use  hard  maple  would  be  a  good  substitute  for  hickory,  except  for 
the  fact  that  it  is  likely  to  have  twisted  or  spiral  grain.  White  oak 
is  too  useful  for  other  purposes  to  be  considered  as  a  substitute  for 
hickory  at  the  present  time.  Moreover,  it  is  somewhat  inferior  to 
hickory  in  strength  and  toughness.  Red  oak,  carefully  selected, 
may  be  used  as  a  substitute  for  the  poorer  grades  of  hickory.  Ash 
also  may  be  substituted  for  hickory  in  some  of  its  uses.  While 


46 


THE   COMMERCIAL   HICKORIES. 


buggy  wheels  have  been  made  of  catalpa,  this  wood  will  never  replace 
hickory,  because  it  has  only  about  one-half  the  strength  of  good 
hickory. 

No  timber  has  been  found  which  has  both  the  strength  and  shock- 
resisting  qualities  of  hickory.  This  is  especially  true  of  small  ma- 
terials, such  as  rims,  spokes,  and  ax  handles. 

FACTORS    THAT   AFFECT    STRENGTH. 

MOISTURE. 

Table  No.  15  shows  the  effects  of  moisture  on  strength.  The 
strength  at  maximum  load  represented  by  the  modulus  of  rupture 
is  about  doubled  by  drying,  and  the  shock-resisting  ability,  or  work 
to  maximum  load,  is  slightly  decreased,  due  to  the  great  decrease  in 
bending  of  the  dry  material. 

TABLE  15. — The  effect  of  moisture  on  strength  of  hickory  from  all  localities. 


Species. 

Green. 

Per  cent 
of 
moisture. 

Specific 
gravity, 
dry. 

Modulus 
of 
rupture. 

Work  to 
maxi- 
mum 
load. 

Pignut              

(Average    . 

55.4 
70.6 
45.2 
62.0 
75.0 
49.3 
57.3 
82.5 
47.2 
59.3 
85.8 
45.3 

0.664 
.731 
.591 
.637 
.700 
.573 
.622 
.703 
.521 
.639 
.702 
.521 

Pounds 
per  sq.  in. 
11,  455 
14,  538 
8,192 
10,561 
13,099 
8,000 
11,  177 
13,  370 
7,911 
10,  340 
13,  988 
7,737 

33.0 
60.0 
16.9 
22.4 
54.1 
8.2 
30.5 
59.7 
9.1 
34.5 
42.2 
11.9 

{High  10  per  cent  

Shagbark 

Low  10  per  cent 

(Average  

<High  10  per  cent 

Mockernut  

[Low  10  per  cent  

(Average 

<  High  10  per  cent  

Big  shellbark 

(Low  10  per  cent 

(Average  

•|  High  10  per  cent 

Pignut 

[Low  10  per  cent  

Air  dry. 

Average  

9.5 
30.3 
8.6 
9.7 
10.5 
9.2 
9.3 
11.2 
8.2 
9.3 
10.4 
8.4 

0.776 
.862 
.648 
,742 
.811 
.666 
.723 
.821 
.666 
.736 
.801 
.627 

23,  482 
27,804 
16,563 
22,  148 
26,760 
17,  953 
20,370 
25,120 
15,370 
19,  724 
25,320 
16,070 

31.2 
52.5 
13.2 
27.8 
47.8 
11  7 
22.1 
37.8 
9.6 
23.6 
38.2 
6.2 

<High  10  per  cent. 

Shagbark 

(Low  10  per  cent  

Average  

<  High  10  per  cent 

Mockernut  

[Low  10  per  cent  ... 

Average 

Maximum  

Big  shellbark 

Minimum 

Average  

Maximum 

Minimum  ,  

THE   WOOD   AND   ITS    MECHANICAL  PROPERTIES. 


47 


WEIGHT. 


Figure  12,  which  includes  all  the  commercial  hickories,  shows  that 
the  work  or  shock-resisting  ability  increases  in  proportion  to  the  dry 
weight  of  the  wood.  The  strength  at  maximum  load  also  appears  to 
increase  almost  in  direct  proportion  to  the  dry  weight.  The  deduc- 


S TRENGTH  A  T  MAX/ MUM  LOA D 

g  |  I 

§ 


.4-50  .500  .550  .600  .650  .7OO  .750 
5PEC/F/C  GftAV/TY 

3  Tests 
STtsts 

\ 

//7S 
2/72 

sfis<? 

.5*5  \ 

44 
t 

ST&sts 
27*Sf, 

\ 

/ 

a 

7OT<£sr 
a97&st 

s  ) 

,( 

\5Q7ti. 
2/67~e 

A 
'«\ 

98. 

JC 

*ests^ 

)7£3tS 

I 

\ 

77G5&. 

6 

BEND/MG  WORK  TO  MAX/ MUM  LOAD 


<+50  .500  .550  .600  .650  .7OO  .7SO 
5PEC/F/C  GKAV/Tr 

3Tes 

s: 

*v 

'ests^p 

//72 
<?/; 

stsd 
esfst) 

46 

T&stsb 
32  Test 

K 

/70Ti 
2E9Tt 

?^z^b 

^5<C 

2587, 
2/ 

«k^ 
STeste. 

\ 

337e 
3O7es 

y^> 
^^ 

77&st± 

>0 

tion  from  figure  12  is  that  hickory  may  be  inspected  upon  a  basis  of 
weight,  and  the  heavier  the  wood  the  better.  Additional  confirma- 
tion of  this  is  found  in  figure  13,a  which  shows  that  the  strength  and 

«  From  Forest  Service  Circular  No.  142,  "Tests  of  Vehicle  and  Implement  Woods." 


48 


THE    COMMERCIAL   HICKORIES. 


resilience  of  spokes  increase  with  the  weight  of  the  spoke.  This  rela- 
tion of  weight  to  strength  is  true  of  various  species,  as  is  shown  clearly 
in  Circular  15  of  the  Division  of  Forestry  a  and  confirmed  by  many 
more  recent  tests. 

RATE    OF   GROWTH. 

Usually  woods  are  selected  on  the  basis  of  appearance,  very  largely 
on  the  rate  of  growth,  as  shown  in  the  cross  section.  In  hickory 
the  wide-ringed  wood,  often  called  "  second-growth "  hickory,  is  pre- 
ferred. Figure  14,  based  on  commercial  hickory  grown  in  good  situ- 


A.: 


^ 


fxxffts 
qroupito  jooipts 


are  oitoiifed 


KH  HO  Bf>  UO  MO  ISO  /60  170  00  190 

WEIGHT  ,„  GRAMS. 

FIG.  13.— Spoke-test  chart,  showing  relation  between  resilience  factor  and  weight  in  clear  spokes. 

ations,  shows  that  the  work  or  shock-resisting  ability  is  greatest  with 
wide-ringed  wood  that  has  from  5  to  14  rings  per  inch ;  is  fairly  con- 
stant from  14  to  38  rings,  and  decreases  rapidly  from  38  to  47  rings 
per  inch.  The  strength  at  maximum  load  is  not  so  great  with  the 
most  rapid-growing  wood ;  it  is  at  a  maximum  with  from  14  to  20  rings 
per  inch,  and  again  becomes  less  as  the  wood  becomes  more  closely 
ringed. 

The  natural  deduction  is  that  wood  of  first-class  mechanical  value 
shows  from  5  to  20  rings  per  inch,  and  that  slower  growth  yields  poorer 


o  Summary  of  Mechanical  Tests  upon  Thirty-two  Species  of  American  Woods. 


THE   WOOD  AND  ITS   MECHANICAL  PKOPERTIES. 


49 


stock.     Thus  the  inspector  or  buyer  of  hickory  should  discriminate 
against  timber  that  has  more  than  20  rings  per  inch.     Exceptions 


STRENGTH AT  MAX/MUM  LOAD 
^  fe 

5  O 

S  S> 


BENO/NG  WORK  TO  MAX/ MUM  LOAD 
5  8  fe  S 


exist,  however,  in  the  case  of  normal  growth  upon  dry  situations,  in 
\vliich  the  slow-growing  material  may  be  strong  and  tough. 


50 


THE  COMMERCIAL  HICKORIES. 


HEARTWOOD    AND    SAPWOOD. 


In  the  case  of  the  hickories  there  is  an  unfounded  prejudice  against 
the  heartwood.  Specifications  place  white  hickory,  or  sapwood,  in 
a  higher  grade  than  red  hickory,  or  heartwood,  though  there  is  no 
inherent  difference  in  strength.  In  fact,  in  the  case  of  large  and  old 
hickory  trees  the  sapwood  nearest  the  bark  is  comparatively  weak, 
and  the  best  wood  is  in  the  heart,  though  in  young  trees  of  thrifty 
growth  the  best  wood  is  in  the  sap. 

TABLE  16. — Comparative  values  of  sapwood  and  heartwood  in  selected  pieces  of  green 
pignut  and  shaybork,  and  in  commercial  hickories  taken  at  random. 


Kind  of  wood. 

Rings  per 
inch. 

Dry  spe- 
cific 
gravity. 

Modulus  of 
rupture. 

Work  to 

maxi- 
mum 
load. 

Selected  pieces  of  pignut  and  shagbark. 
Heartwood  (south)  

Number. 
19.5 

0.628 

Pounds  per 
square  inch. 
11,800 

Inch 
pounds 
per  cu.  in. 
22.4 

Heartwood  (north)  

16.0 

.683 

10,600 

31.2 

Sapwood  (south) 

18  4 

.599 

11,130 

20  2 

Sapwood  (north)  

16.6 

.664 

12,160 

33.  1 

Average  heartwood  

17.3 

.667 

11,070 

28.1 

Average  sapwood 

17  4 

.639 

11,790 

28  5 

Commercial  hickory  of  several  species. 
Heartwood  (south) 

22.0 

.632 

11,080 

26  8 

Heartwood  (north) 

20  9 

660 

10  322 

31  4 

Sapwood  (south) 

19.0 

.588 

11,065 

22  9 

Sapwood  (north)  

15.0 

.672 

11,693 

?6.0 

Average  heartwood  

21.0 

.648 

10,630 

29.4 

Average  sapwood 

17.0 

.640 

11,509 

30.4 

Table  16  gives  the  results  of  tests  from  selected  pieces  lying  side 
by  side  in  the  same  tree,  and  also  the  average  values  for  heart- 
wood  and  sapwood  in  shipments  of  the  commercial  hickories  without 
selection.  It  shows  conclusively  that  the  transformation  of  sapwood 
into  heartwood  does  not  affect  either  the  strength  or  toughness  of  the 
wood.  This  conclusion  is  also  confirmed  by  Forest  Service  Circular 
142,  which  shows  that,  weight  for  weight,  sound  hickory  is  equally 
strong,  regardless  of  color.  Therefore  the  user  of  hickory  should  not 
discriminate  against  heartwood  in  buying  stock.  It  is  true,  how- 
ever, that  sapwood  usually  is  more  free  from  latent  defects  than 
heartwood. 


POSITION    IN    THE    TREE. 


The  determination  of  the  strength  of  material  at  various  distances 
from  the  center  of  the  tree  toward  the  bark  gives  a  good- indication 
of  the  effect  of  growth  on  strength.  In  trees  from  forests  which  have 
grown  for  a  long  time  under  fixed  conditions  it  is  necessary  only  to 
take  a  specimen  from  a  predetermined  point  in  the  cross  section  at  a 
given  height  to  determine  a  factor  which  represents  the  mechanical 


THE    WOOD   AND   ITS    MECHANICAL   PROPERTIES. 


51 


STRENGTH  AT  MAX/ MUM  LOAD 

*         §         i 
§         §         § 


BENO/NG  WORK  TO  MAX/MUM  LOAD 
*.  fe  S»  4 


a  <*•  £ 

/MCHE5-FROM  C 
ty  as  affected  by  posit 

/o 

ITesfst 

/3 

tO1*^^ 

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zstsp 

?  a  /o 

'ENTER  OF  TREE 

ion  in  the  tree,  as  sh 

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7  > 

estsO 

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52  THE   COMMERCIAL  HTCKORIES. 

value  of  the  wood  in  the  tree.  This  procedure  is,  however,  not  pos- 
sible with  American  woods,  because  silvical  conditions  have  not 
become  constant,  and  the  origin  and  history  of  the  tree  are  unknown. 

Figure  15  shows  the  results  of  tests  to  determine  the  strength  in 
relation  to  the  distance  from  the  center  of  the  tree.  In  normal  trees, 
the  strongest  wood  appears  to  be  from  5  to  7  inches  out  from  the 
center  of  the  tree,  and  wood  of  greatest  shock-resisting  ability  is  nearly 
in  the  center;  consequently  the  wood  3  to  7  inches  from  the  center 
of  the  tree  is  the  best.  However,  suppression  and  slow  growth  in 
youth,  followed  by  exposure  to  light  and  fast  growth  in  old  age,  will 
disturb  these  relations,  and  under  such  conditions  the  best  wood  may 
be  found  near  the  outer  part  of  the  tree. 

The  entire  merchantable  boles  of  two  trees  were  used  to  determine 
the  relation  of  height  above  ground  to  strength  and  toughness  (see 
fig.  16).  The  butt  cuts  were  toughest  but  not  strongest;  the  strong- 
est wood  was  from  21  to  30  feet  above  the  ground.  The  toughest 
wood  is  in  the  butt,  and  above  the  butt  the  technical  value  of  the 
wood  remains  practically  constant  up  to  the  base  of  the  crown,  where 
it  becomes  less  valuable.. 

AGE. 

Trees  about  150  years  old  have  the  maximum  average  strength, 
but  the  average  work  to  maximum  load  is  less  with  increasing  age, 
and  the  youngest  trees  are  toughest.  Therefore,  to  obtain  the  best 
wood  the  trees  should  not  be  allowed  to  become  overmature. 

SOIL   AND   SITUATION. 

In  some  regions  there  are  many  small,  stunted  hickories,  which 
most  users  will  not  touch.  They  have  narrow  sap,  are  likely  to  be 
birdpecked,  and  show  very  slow  growth.  Yet  five  of  these  trees 
from  a  steep,  dry  south  slope  in  West  Virginia  had  an  average  strength 
fully  equal  to  that  of  the  pignut  from  the  better  situation,  and  were 
superior  in  toughness,  the  work  to  maximum  load  being  36.8  as 
against  31.2  for  pignut.  The  trees  had  about  twice  as  many  rings 
per  inch  as  others  from  better  situations. 

This,  however,  is  not  very  significant,  as  trees  of  the  same  species, 
age,  and  size,  growing  side  by  side  under  the  same  conditions  of  soil 
and  situation,  show  great  variation  in  their  technical  value.  .  It  is 
hard  to  account  for  this  difference,  but  it  seems  that  trees  growing 
in  wet  or  moist  situations  are  rather  inferior  to  those  growing  on 
fresher  soil;  also,  it  is  claimed  by  many  hickory  users  that  the  wood 
from  limestone  soils  is  superior  to  that  from  sandy  soils. 

GEOGRAPHIC   LOCATION. 

One  of  the  moot  questions  among  hickory  men  is  the  relative 
value  of  northern  and  southern  hickory.  The  impression  prevails 
that  southern  hickory  is  more  porous  and  brash  than  hickory  from 


THE   WOOD  AND  ITS   MECHANICAL  PROPERTIES. 


53 


the  north.     The  tests  summarized  in  Table  17  indicate  that  southern 
hickory  is  as  tough  and  strong  as  northern  hickory  of  the  same  age. 

5  TRENGTH  AT  MAX/ MUM  LOAD 


FE 

.  16. 


BO 

engt 


jo  to 
VE  GROUND 


BEMD/NG  WORK  TO  MAX/  MUM  LOAD 


SPEC/F/C  GRAV/TY 
\  I 


/O  SO  JO  <H3  S 

FEET  ABOVE  GROUND 

\"\\  by  tests  on  green  hickory. 

1 

Q 

But  the  southern  hickories  have  a  greater  tendency  to  be  shaky,  and 
this  results  in  much  waste.     In  trees  from  southern  river  bottoms 


54 


THE   COMMERCIAL  HICKORIES. 


the  loss  through  shakes  and  grub  holes  in  many  cases  amounts  to 
as  much  as  50  per  cent. 

TABLE  17. — Comparison  of  strength  and  toughness  of  northern  and  southern  hickories  of 

the  same  age. 


Location. 

Number 
of  trees. 

Age. 

Number 
of  tests. 

Rings 
per  inch. 

Southern  hickories 

8 

260 

120 

Number. 
18.2 

Northern  hickories  

16 

266 

127 

22.6 

Specific 

gravity 

dry. 


0. 621 
.637 


Modulus 
of  rup- 
ture. 

Work  to 
maxi- 
mum, 
load. 

Inch 

Pounds 

pounds 

per  sq.  in. 

per  cu.  in. 

11,544 

24.1 

10,581 

22.8 

TABLE  18. — Summary  of  static  bending  tests  of  various  hickories  from  several  localities. 


Species. 

Mississippi.                                         Ohio. 

Per 

cent  of 
mois- 
ture. 

Dry 
specific 
gravity. 

Modu- 
lus of 
rup- 
ture. 

Work 
to  max- 
imum 
load. 

Per 
cent  of 
mois- 
ture. 

Dry 
specific 
gravity. 

Modu- 
lus of 
rup- 
ture. 

Work 
to  max- 
imum 
load. 

Pignut  

Shagbark 

Average  

60.2 
77.5 
48.6 
64.5 
77.5 
50.8 
63.8 
85.0 
»    47.7 
63.5 
82.0 
46.9 

0.628 
.679 
.560 
.613 
.664 
.562 
.606 
.676 
.510 
.612 
.679 
.514 

Pounds 
per  sq. 
in. 
11,800 
13,866 
9,880 
11,210 
12,838 
8,755 
11,310 
13,038 
8,462 
10,890 
13,950 
7,805 

Inch 
pounds 
per  cu. 
in. 
26.8 
44.8 
12.2 
20.6 
41.0 
8.7 
23.6 
52.8 
8.6 
30.6 
60.8 
10.5 

54.1 
65.1 
46.0 
59.1 
74.3 
49.5 

0.  661 
.713 

.597 
.648 
.707 
.579 

Pounds 
per  si. 
in. 
11,820 
14,430 
8,425 
10,610 
13.225 
7,961 

Inch 

pounds 
per  cu. 
in. 
31.4 
58.2 
12.6 
•  34.4 
59.9 
12.4 

High  10  per  cent.  . 
Low  10  percent.  . 
Average  . 

High  10  per  cent.. 
Low  10  per  cent.  . 
(Average 

Mockernut 

\  High  10  per  cent.. 
(Low  10  per  cent.  . 
A  verage 

Bigshellbark.... 
Bitternut 

55.2 

69.8 
47.6 
65.6 
79.0 
50.3 

.667 
.729 
.625 
.622 
.658 
.573 

9,790 
11,896 
7,212 
10,030 
12,  622 
7,463 

38.5 
55.5 
18.4 
30.9 
58.6 
8.3 

High  10  per  cent.  . 
(Low  10  per  cent.  . 
(Average 

High  10  per  cent 

Nutmeg  hickory  . 
Water  hickory  

Low  1  0  per  cent 

75.9 
93.0 
61.0 
75.5 
98.6 
51.0 

.567 
.620 
.488 
.625 
.720 
.552 

9,200 
11,575 
6,773 
10,  329 
11,966 
8,893 

23.9 
40.8 
11.3 
18.1 
30.8 
8.9 

High  10  per  cent.  . 
Low  10  per  cent.  . 

High  10  per  cent^ 
Low  10  percent.  . 

Species. 

West  Virginia. 

Pennsylvania. 

Per 
cent  of 
mois- 
ture. 

Dry 

specific 
gravity. 

Modu- 
lus of 
rup- 
ture. 

Work 
to  max- 
imum 
load. 

Per 
cent  of 
mois- 
ture. 

Dry 

specific 
gravity. 

Modu- 
lus of 
rup- 
ture. 

Work 
to  max- 
imum 
load. 

Pignut 

Average  

51.8 
64.9 
43.9 
60.8 
71.7 
48.1 
49.3 

0.677 
.746 
.606 
.656 
.696 
.585 
.666 

Pounds 
per  sq. 
in. 
11,430 
15,000 
8,385 
10,770 
13,131 
7,837 
12,  120 

Inch 
pounds 
per  cu. 
in. 
32.6 
59.7 
10.4 
18.8 
40.9 
6.2 
32.6 

55.5 

69.7 
44.9 
63.7 

0.677 
.726 
.595 
.630 

Pounds 
per  sq. 
in. 
11,114 
14,425 
7,920 
9,655 

Inch 
pounds 
per  cu. 
in. 
37.1 
65.8 
9.4 
15.9 

High  10  per  cent. 
Low  10  per  cent. 
Average 

Shagbark 

High  10  per  cent. 
Low  10  per  cent. 
Average  

Mockernut  

58.7 
67.1 

48.8 

.658 
.728 
.584 

10,100 
14,  132 
7,338 

35.4 
59.6 
13.6 

High  10  per  cent 

Low  10  per  cent 

THE    WOOD   AND   ITS    MECHANICAL   PROPERTIES.  55 

In  this  connection,  attention  may  be  called  to  the  low  value  of 
green,  eastern  shagbark,  as  shown  in  Table  18  and  figure  17,  as  com- 
pared to  that  of  Ohio  and  Mississippi.  This  is  hard  to  explain,  but 
corroborates  the  prejudice  which  some  eastern  users  have  against 
shagbark.  Dry  specimens  do  not  show  this  inferiority. 

A  more  thorough  study  will  be  necessary  before  definite  conclusions 
can  be  drawn. 

It  is  clear,  therefore,  that  the  difference  in  northern  and  southern 
hickory  is  not  due  to  geographic  location,  but  rather  to  the  character 
of  timber  that  is  being  cut.  Nearly  all  of  that  from  southern  river 
bottoms  and  from  the  Cumberland  Mountains  is  from  large,  old- 
growth  trees;  that  from  the  north  is  from  younger  trees  which  are 
grown  under  more  favorable  conditions,  and  it  is  due  simply  to  the 
greater  age  of  the  southern  trees  that  hickory  from  that  region  is 
lighter  and  more  brash  than  that  from  the  north. 


SPECIES. 


According  to  Tables  15  and  18  and  figure  17,  pignut,  which  is  gen- 
erally considered  best,  is  actually  the  strongest  and  toughest  and  is 
comparatively  uniform  for  all  regions.  Shagbark  is  only  slightly 
inferior  to  pignut;  big  shellbark  is  of  only  medium  strength,  but 
is  inferior  to  no  other  species  in  toughness;  mockernut  is  somewhat 
stronger  than  big  shellbark,  but  lacks  toughness. 

The  pecan  hickories  are  very  little  used  throughout  the  region 
where  hickory  is  €ut,  and  spoke  and  handle  makers  consider  them 
inferior;  the  few  tests  which  were  made  suffice  at  least  to  show  that 
this  prejudice  is  well  founded.  JBitternut  from  northern  Ohio,  which 
was  of  the  best  quality  of  second  growth,  is  slightly  inferior  to  other 
hickories  from  the  same  region.  Nutmeg  and  water  hickories  are 
characteristically  shaky,  and  the  tests  show  that  the  wood  is  inferior 
to  that  of  the  true  hickories. 

Strength  and  toughness  vary  greatly  within  the  same  species. 
Thus,  although  pignut  from  Pennsylvania  is  very  strong  and  tough, 
it  will  yield  much  material  which  is  no  better  than  the  average  of  the 
pool-  species  grown  is  less  favorable  localities.  In  general,  the  lowest 
grades  of  the  best  of  the  true  hickories  are  no  better  than  the  average 
of  the  poorest  pecan  hickories.  While,  therefore,  the  different  species 
have  different  average  values — and  this  is  an  important  consideration 
in  forest  management  and  in  the  buying  of  trees  in  the  woods — the 
selection  of  the  best  hickory  in  the  yard  can  not  be  based  on  anything 
but  a  most  rigid  inspection  and  grading.  The  pecan  hickories  all 
produce  inferior  timber,  and  true  pecans,  if  grown  for  the  commercial 
value  of  their  fruits,  should  not  be  seedlings,  but  named  varieties, 
grafted  or  budded. 


56 


THE  COMMERCIAL  HICKORIES. 
STRENGTH  AT  MAX/ MUM  LOAD 


M/SS. 


OH/0 


f  PIGNUT 

SHAG  BARK 
I     MOCKER    NUT 
\     BfG   SHELL.BARK 
NUTMEG  HICKOi 
\^WATER  HICKORY 

fPlGNUT 

I    SHAG  BARK 

I     B/G  SHELL  BARK 

V.  BITTERN  UT 


f  PIGNUT 
W.VA.      <    SHAG  BARK 

NUT 


r  PIG  NUT 

PEMN.    <     5HAGBARK 

\.MOCKER  NUT 


BEMD/MG  WORK  TO  MAX/ MUM  LOAD 


M/SS.    < 


OH/O 


'PIGNUT 
5HAGBARK 
MOCKER  NUT 
BIG  SHELLBARK 
NUTMEG  HICKORY 
HIGKORY 


f PIGNUT 

I    SHAGBARK 

|     BIS  SHELLBARK 

V  BITTER  NUT 


f  PIGNUT 
W.VA.       <     SHAGBARK 

\.  MOCKER  NUT 

f  PIG  NUT 
<    SHAGBARK 


FIG.  17.—  Relative  values  of  the  various  species  of  hickory,  as  compared  on  the  basis  of  static 

bending  tests. 


OUTLOOK   FOR  FUTURE   SUPPLY.  57 

DEFECTS. 

Iron  streaks  and  birdpecks  of  small  size  do  not  appear  to  affect  the 
strength  or  toughness  of  hickory.  Hair  checks  are  usually  found 
in  the  heavier  and  better  timber,  and  have  but  little  effect  upon  the 
strength  and  toughness.  Cross  and  spiral  grain  and  dips  in  grain  are 
all  serious  defects,  and  greatly  reduce  strength  and  toughness.  The 
weakening  effect  of  knots  is  due  chiefly  to  the  cross  grain  which  they 
cause. 

OUTLOOK  FOB  FUTURE  SUPPLY. 

A  shortage  in  the  hickory  supply  is  imminent.  Virgin  hickory, 
which  has  hitherto  furnished  the  chief  supply,  is  disappearing  rapidly, 
and  there  are  no  foreign  sources  which  can  be  drawn  upon  when  the 
home  supplies  are  exhausted.  It  will  soon  be  necessary,  therefore, 
to  depend  entirely  upon  the  second  growth.  The  maintenance  of  the 
supply  is  of  vital  concern,  because  no  satisfactory  substitute  has  as 
yet  been  found. 

Forest  owners,  with  some  justice,  regard  the  hickories  as  inferior 
trees,  but  there  is  one  important  consideration  in  their  favor;  large 
sizes  are  not  required.  With  oak,  black  walnut,  black  cherry,  yellow 
poplar,  and  other  important  hardwood  trees,  there  is  a  great  increase 
in  value  with  size,  because  the  heartwood  is  most  valuable  and  timber 
of  large  dimensions  is  needed.  But  with  hickory,  the  only  increase 
in  value  with  size  comes  from  the  increased  number  or  size  of  the 
clear  billets  or  strips  which  can  be  obtained  from  a  tree.  Sap  wood 
is  now  preferred  to  heartwood  and  the  younger  and  faster-grown 
material  is  tougher  than  the  older  and  the  slower  grown.  For  most 
of  its  uses  hickory  can  be  cut  when  it  is  8  or  9  inches  in  diameter  and 
from  40  to  60  years  old,  while  oak  generally  must  be  from  18  to  20 
inches  in  diameter  and  from  100  to  120  years  old.  Even  hickory, 
however,  can  not  be  cut  so  early  as  can  catalpa  and  black  locust  for 
fence  posts,  cottonwood  and  yellow  poplar  for  pulp,  chestnut  for  ties 
and  poles,  and  white  .pine  for  box  boards,  and  all  of  these  grow  faster 
than  hickory.  Moreover,  the  yield  of  hickory  per  acre,  as  is  usual 
with  trees  which  produce  a  hard,  heavy  wood,  is  comparatively  low. 

For  similar  sites  and  areas,  the  total  volume  production  of  white 
pine  is  at  least  three  times  that  of  hickory;  of  catalpa,  yellow  poplar, 
and  chestnut  at  least  twice  as  much  as  hickory;  and  of  ash,  black 
walnut,  and  white  oak  at  least  from  one-third  to  one-half  more. 
Then,  too,  the  demands  of  the .  hickory  trade  are  very  exacting. 
Generally  less  than  half  the  total  volume  is  used,  whereas,  with  white 
pine  and  other  conifers  the  utilization  is  very  close;  in  New  England, 
for  instance,  more  than  90  per  cent  of  the  total  volume  of  white  pine 
is  used.  Even  the  other  hardwoods,  such  as  chestnut,  white  ash,  and 
yellow  poplar,  are  utilized  more  closely  than  hickory.  Yet  present 
prices  do  not  take  these  facts  into  account,  and  even  at  the  compara- 


58  THE   COMMERCIAL  HICKORIES. 

tively  high  stumpage  price  of  $10  a  cord  a  fully  stocked  stand  of 
hickory  50  years  old  is  worth  only  about  $80  an  acre,  while  a  white- 
pine  stand  of  the  same  age  at  the  low  stumpage  value  of  $5  per 
thousand,  or  approximately  $2.50  a  cord,  would  be  worth  $200.  On 
rich  soils  catalpa  has  yielded  more  than  $200  per  acre  at  the  end  of 
twenty  years.  In  short,  it  does  not  pay  to  raise  hickory  when  it  is 
possible  to  raise  chestnut,  catalpa,  black  walnut,  or  yellow  poplar. 
Therefore,  the  forest  owner  who  considers  only  present  prices,  and  the 
slow  growth  and  low  yield  per  acre,  is  likely  to  cut  out  his  hickories 
to  make  room  for  faster-growing  species;  and  he  will  never  plant 
hickory. 

Prices,  however,  are  bound  to  advance,  because  of  the  high  technical 
value  of  hickory,  coupled  with  the  fast-diminishing  supply.  Current 
prices  can  advance  considerably  without  affecting  the  trades.  At 
present  the  stumpage  values  range  from  2  to  33  per  cent  of  the  value 
of  the  finished  product  and  average  less  than  10  per  cent.  The  costs 
of  manufacture  and  of  transportation  are  still  the  largest  item  in  the 
cost  of  a  spoke  or  of  a  rim  strip.  Unless  some  entirely  new  material 
is  found  to  take  the  place  of  hickory,  and  this  seems  quite  improbable, 
it  is  only  a  question  of  time  when  the  prices  will  advance  sufficiently 
to  place  hickory  on  an  equal  footing  with  chestnut,  poplar,  and  other 
faster-growing  species;  even  now  it  is  practically  on  an  equal  footing 
with  white  oak  and  white  ash,  the  other  trees  most  important  for 
toughness  and  strength  used  for  purposes  similar  to  those  for  which 
hickory  is  used. 

With  the  hickories  on  an  even  footing  with  other  important  timber 
trees,  with  the  hardwood  forests  of  the  country  under  proper 
management,  and  with  the  drain  decreased  through  a  lessening  of 
waste,  there  should  be  no  difficulty  in  producing  all  the  hickory 
that  is  needed  for  home  consumption,  with  some  over  to  supply  much 
of  the  foreign  demand. 

There  are  now  about  100,000,000  acres  of  forest  land  on  which 
hickory  is  growing  naturally,  although  not  necessarily  in  pure  stands. 
In  most  places  the  forest  has  been  wastefully  cut  and  severely  burned 
and  pastured,  so  that  it  is  in  a  low  productive  condition.  It  must 
soon  become  the  object  of  care  and  attention.  Because  of  their 
naturally  good  reproduction,  their  ability  to  endure  shade  and  to 
grow  under  many  different  conditions  of  soil  and  climate,  the  hickories 
are  particularly  amenable  to  forest  management,  and  a  little  intelligent 
care  can  greatly  better  both  quantity  and  quality  of  the  yield. 

METHODS    OF   PERPETUATING   THE    SUPPLY. 

The  two  principal  methods  by  which  the  supply  can  be  maintained 
are  economic  and  silvicultural.  The  first  depends  upon  hickory 
users,  and  will  consist  in  reducing  waste  and  improving  the  economic 


OUTLOOK   FOR  FUTURE   SUPPLY.  59 

position  of  the  tree;  the  second  lies  in  the  hands  of  the  forest  owners, 
and  will  consist  in  the  proper  care  of  the  tree  in  the  forests  with  a 
consequent  increase  in  the  quantity  and  betterment  of  the  quality 
of  the  crop.  User  and  producer  must  act  together,  for  without  a 
reduction  of  waste  there  will  be  too  severe  a  tax  on  the  hickory 
resources  to  produce  enough  timber  even  with  special  attention  given 
to  the  production  of  a  greater  supply.  Without  an  improvement  in 
the  economic  position  of  the  tree,  no  attention  will  be  paid  to  the 
production  of  new  supplies,  and  hickory  will  still  be  cut  out  to  make 
room  for  faster-growing  trees.  The  problem  therefore  lies  primarily 
in  the  hands  of  the  hickory  users,  and  it  will  be  necessary  to  secure 
closer  cooperation  among  them  through  such  organizations,  for 
instance,  as  the  National  Hickory  Association. 


ECONOMIC    MEANS. 


For  the  prevention  of  waste,  the  following  recommendations  are 
made: 

1.  Grading  rules  should  be  revised  to  stop  unjust  discrimination 
against  heartwood  and  birdpecks.     This  will  do  away  with  most  of 
the  waste,  and  if  such  new  rules  are  put  in  operation  and  made 
effective,  they  should  reduce  the  annual  cut  at  least  15  per  cent. 
Fortunately,  steps  have  already  been  taken  toward  this  end  by  the 
National  Hickory  Association. 

2.  Overproduction  should  be  prevented,  because  hickory  wood  is 
so  quickly  attacked  by  borers  that  material  which  is  not  immediately 
disposed  of  is  almost  invariably  subject  to  heavy  loss.     Manufactur- 
ers' associations  have  already  taken  some  action  along  this  line. 

3.  There  should  be  less  specialization  in  the  manufacture  of  hickory. 
For  instance,  skewers,  small  handles,  and  dowel  pins  could  and  should 
be  manufactured  only  as  by-products  in  the  making  of  spokes,  ax 
handles,  rims,  and  shafts,  and  spokes  and  handles  can  be  made  in 
connection  with  rim  or  pole  and  shaft  operations.     This  will  not 
only  permit  a  closer  utilization  of  material  at  the  mill  but  will  make 
it  possible  to  utilize  more  closely  in  the  woods.     Economy  of  this 
sort*  is  now  practiced  by  many  companies,  but  it  should  be  carried 
much  further.     The  best  example  of  the  wastefulness  of  the  present 
methods  is  the  riving  out  of  spoke  billets  and  handle  blanks  in  the 
woods.     The  superior  quality   of  rived   billets   and  spokes   is   due 
largely  to  the  fact  that  only  the  best  material  is  taken  and  the  rest 
is  left  or,  perhaps,  sold  as  firewood.     Sawing  should  be  substituted 
for  riving,  because,  by  sawing,  many  more — often  twice  as  many — 
spokes  and  handles  can  be  gotten  out,  and  much  of  the  present  waste 
can  be  utilized  for  hammer  and  hatchet  handles,  skewers,   dowel 
pins,  and  other  uses. 


60  THE   COMMERCIAL  HICKORIES. 

To  place  the  hickories  upon  an  equal  commercial  footing  with 
other  trees,  two  measures  are  imperative.  In  the  first  place,  a  cubic 
foot  log  rule  should  replace  the  inaccurate  and  unjust  rules  now  in 
use.  In  buying  and  selling  any  commodity,  a  standard  of  measure- 
ment is  fair  only  when  both  parties  to  the  transaction  understand 
just  what  it  means,  but  the  hickory  rules  now  in  use  confuse  even  the 
experienced  lumberman,  to  say  nothing  of  the  inexperienced  wood- 
lot  owner.  The  cubic  measure,  used  everywhere  in  Europe  and  in 
some  places  in  this  country,  is  much  more  accurate  and  satisfactory 
for  general  use  than  the  board  foot  measure,  and  it  is  especially 
applicable  in  the  case  of  hickory,  because  it  is  not  usually  cut  into 
boards  or  planks  but  into  piece  stock.  The  adoption  of  the  rule 
given  in  Table  13,  which  applies  especially  to  the  hickories,  is  therefore 
strongly  urged. 

In  the  second  place,  there  should  be  a  general  advance  in  prices  to 
permit  of  higher  stumpage  values.  It  is  inevitable  that  such  an 
advance  must  come,  and  the  sooner  the  advance  begins  and  the  atten- 
tion of  forest  owners  is  drawn  to  the  value  of  hickory,  the  less  danger 
there  will  be  of  a  serious  shortage  with  accompanying  high  prices  and 
general  inconvenience.  Higher  prices,  moreover,  will  not  only 
encourage  the  care  of  the  hickory  in  the  forest,  but  will  also  be  a 
most  effective  means  of  reducing  waste  and  forcing  closer  utilization. 


SILVICULTURAL   MEANS. 


To  produce  spoke  and  handle  material,  which  takes  more  than 
half  the  annual  cut  of  hickory,  no  method  seems  better  than  reproduc- 
tion by  sprouts.  Sprouts  grow  faster  than  seedlings  for  the  first  fifty 
or  sixty  years,  and  produce  heavier  yields  per  acre;  where  sprout 
reproduction  is  at  all  successful  it  is  less  uncertain  than  seedling 
reproduction. 

A  simple  clear-cutting  for  coppice  growth,  which  can  be  used  with 
oak  and  chestnut,  will  not,  however,  apply  to  hickories  as  they  occur 
in  mixed  stands,  because  faster-growing  species  invariably  outstrip 
and  suppress  the  hickories  so  that  they  appear  only  on  the  edges  or 
in  the  openings  of  such  mixed  stands.  But  there  are  many  old  fields 
and  pastures,  especially  in  the  Ohio  Valley,  which  are  coming  up  to 
pure  stands  of  hickory,  and  there  the  coppice  method  could  be  applied 
successfully.  Since  the  sprouting  capacity  falls  off  very  rapidly  as 
the  tree  grows  older,  the  cutting  should  begin  as  soon  as  the  trees  are 
large  enough  to  use,  which  will  be  when  they  are  from  8  to  9  inches 
in  diameter  and  from  40  to  50  years  old.  The  stand  may  then  be  cut 
clear. 

Pure  stands,  however,  are  uncommon  and  it  will  often  be  advisable 
to  plant  hickory  with  the  idea  of  ultimately  managing  it  as  a  sprout 


OUTLOOK   FOR  FUTURE   SUPPLY.  61 

forest.  Because  of  the  danger  from  squirrels  and  mice,  fall  planting 
should  not  be  attempted.  The  nuts  should  be  kept  over  winter 
between  layers  of  sand  and  planted  in  the  spring,  and  since  the  long 
taproot  makes  transplating  impracticable,  the  nuts  should  be  planted 
directly  in  the  permanent  site,  and  never  in  a  nursery.  The  spacing 
should  be  about  5  by  5  feet  and  two  or  perhaps  three  nuts  should  be 
placed  in  each  spot  about  2  inches  under  the  surface,  or  it  might  be 
well  to  try  a  group  mixture  with  a  light-seeding  species,  such  as 
white  ash. 

Care  should  be  taken  to  plant  only  those  species  which  are  suited 
to  the  soil  conditions.  On  exposed  situations  or  on  dry  or  sandy 
soils  pignut  is  to  be  preferred,  and  even  that  demands  a  moderate 
amount  of  fertility  to  produce  timber  of  good  quality.  On  moist  or 
wet  soils  big  shellbark  should  be  selected,  and  on  fresh,  fertile  soils 
either  shagbark  or  pignut.  The  latter  furnishes  the  better  grade  of 
wood,  but  the  vjalue  of  the  nuts  is  a  consideration  in  favor  of  the 
former.  A  plantation  of  shagbark  would  begin  to  bear  about  the 
thirtieth  year,  and  from  then  on  it  should  average  scarcely  less  than 
10  bushels  of  nuts  per  acre.  Bitternut,  nutmeg  hickory,  and  water 
hickory  are  inferior  species  and  should  not  be  planted;  mockernut 
has  nothing  to  commend  it  over  pignut;  and  pecan  is  valuable 
chiefly  only  for  its  nuts. 

To  secure  the  normally  rapid  growth  essential  to  the  production 
of  strong  wood,  the  stand  should  not  be  allowed  to  become  over- 
crowded. Thinning  should  begin  about  the  twenty-fifth  year. 
The  crooked  or  defective  trees  and  those  which  are  being  crowded 
and  have  not  room  enough  to  grow  should  be  removed.  This  will 
yield  from  2  to  3  cords  of  firewood  and  will  leave,  perhaps,  800  trees 
to  the  acre.  Eight  or  ten  years  later  the  thinning  may  be  repeated. 
This  should  yield  about  3  cords  of  firewood  and  perhaps  a  few  handle 
bolts,  and  will  leave,  perhaps,  400  trees  to  the  acre.  At  the  end  of 
the  next  ten  years,  if  the  soil  is  fertile,  it  is  barely  possible  that  the 
stand  may  be  ready  to  cut,  but  since  seedling  stands  grow  more 
slowly  than  sprout  stands,  it  will  usually  be  necessary  to  wait  an 
additional  ten  years  before  cutting.  In  this  case  another  ten-year 
thinning  should  be  made,  which  should  leave  about  200  trees  to  the 
acre,  and  should  yield,  perhaps,  a  cord  of  spoke  or  handle  bolts  and 
2  or  3  cords  of  firewood.  By  the  fiftieth  or  sixtieth  year  the  stand 
should  be  merchantable,  and  should  then  be  cut  and  managed  as  a 
sprout  forest. 

In  uneven-aged,  mixed  forest,  where  the  clear-cutting  sprout 
method  can  not  be  used,  hickory  can  readily  be  reproduced  by  the 
selection  system.  In  fairly  open  mixed  stands  hickory  reproduces 
well  and  forms  clean,  straight  stems  under  the  partial  shade  of  older 


62  THE   COMMERCIAL   HICKORIES. 

trees  and  produces  the  heaviest,  strongest,  and  toughest  wood. 
Since  the  best  material  is  obtained  from  thrifty  trees,  the  object  of 
management  should  be  to  make  the  hickories  clean  themselves  early, 
and  then,  after  sufficient  clear  length  has  been  formed,  to  make  them 
grow  fast.  For  this  purpose  the  ax  should  be  used  freely  wherever 
it  is  possible  to  utilize  the  thinnings.  Such  inferior  species  as  beech, 
maple,  black  oak,  elm,  and  bitternut,  as  well  as  defective  trees  of 
all  species,  should  be  cut  out  wherever  they  interfere  with  the  shag- 
barks,  pignuts,  big  shellbarks,  and  mockernuts.  These  thinnings 
should  be  repeated  every  eight  to  ten  years  until  the  forest  assumes 
the  form  of  a  rather  open  upper  story  of  thrifty  hickory,  white  oak, 
black  walnut,  yellow  poplar,  and  ash,  with  an  understory  of  young 
growth,  largely  young  hickory.  Intelligent  cutting  thus  can  increase 
greatly  the  proportion  of  hickory  in  the  forest  and  can  improve  the 
quality  of  the  wood  by  hastening  its  growth.  In  such  a  forest  the 
hickories  finally  should  be  cut  when  they  have  reached  a  diameter 
of  about  12  inches.  At  this  diameter,  on  moderately  good  soil,  they 
will  be  increasing  in  volume  at  the  rate  of  about  4  per  cent  a  year; 
at  14  inches  the  increase  is  about  3  per  cent,  and  at  16  inches  2J 
per  cent. 

It  will  not  be  wise,  however,  to  establish  a  hard  and  fast  diameter 
limit,  because  the  condition  in  which  the  stand  is  to  be  left  must  be 
taken  into  consideration.  Smaller  trees  may  be  cut  wherever  there 
is  promising  young  growth  to  take  their  places.  If  it  is  desired  to 
increase  still  further  the  proportion  of  hickories  in  the  stand,  the 
trees  should  be  left  longer,  and  they  must  also  be  left  longer  where 
the  other  species  are  cut  to  a  large  diameter  limit  or  where  it  is 
impossible  to  give  the  stand  much  attention.  In  mountainous  and 
inaccessible  regions,  therefore,  where  oak  is  cut  to  a  diameter  limit 
of  18  or  20  inches  and  inferior  species  and  defective  trees  are  usually 
left,  the  hickories  should  hardly  be  cut  to  a  smaller  diameter  than 
15  inches. 

Particular  attention  should  be  given  to  protecting  the  young 
growth.  Woodlot  owners  should  make  special  provision  for  this  in 
the  contracts  for  the  sale  of  stumpage.  The  cutting  of  hoop  poles 
should  be  discouraged,  and  it  is  a  fortunate  fact  that  the  business  is 
now  becoming  unprofitable.  The  straightest,  cleanest  saplings  inva- 
riably are  cut,  and  scrubby,  knotty,  and  crooked  specimens  are  left 
to  form  the  basis  of  the  future  crop.  Pasturing  should  be  prohib- 
ited, and  every  means  possible  should  be  taken  to  guard  against  fire. 

SUMMARY. 

On  the  economic  side  the  following  facts  are  apparent:  Hickory 
has  a  number  of  important  special  uses  for  which  no  satisfactory 
substitute  is  known,  and  the  hickory  of  commerce  is  derived  almost 


SUMMARY.  63 

entirely  from  the  true  hickories,  pignut,  shagbark,  mockernut,  and 
big  shell  bark.  The  supply  of  large  hickory,  which  hitherto  has  been 
depended  on,  is  rapidly  approaching  exhaustion,  and  it  will  soon  be 
necessary  to  depend  entirely  upon  the  second  growth.  Since  the 
hickory-producing  woodland  is  owned  mainly  in  small  holdings,  such 
as  farmers'  woodlots,  the  perpetuation  of  the  supply  depends  largely 
on  the  care  of  these  woodlots  by  individuals.  Stumpage  prices  are 
comparatively  low,  and  the  economic  position  of  the  tree  is  still  fur- 
ther lowered  by  unjust  and  inaccurate  log  rules.  Of  the  merchant- 
able hickory  cut  each  year  fully  40  per  cent  is  wasted. 

From  the  silvicultural  standpoint,  as  compared  with  other  impor- 
tant timber  trees,  the  hickories  are  slow  growing,  produce  a  low 
yield  per  acre,  and  are  exacting  in  their  soil  and  moisture  require- 
ments; but  they  are  long-lived,  tolerant  of  shade,  and  there  is  good 
natural  reproduction  both  from  seed  and  from  sprout.  The  wood 
produced  is  superior  in  toughness  and  strength  to  any  other  commer- 
cial wood.  Among  the  different  species  pignut  is  not  only  best 
because  it  is  best  adapted  to  forest  management,  but  also  because  of 
the  value  of  its  wood,  though  shagbark  is  to  be  preferred  where  the 
value  of  the  nuts  is  an  important  consideration.  Big  shellbark  is  a 
good  tree  for  moist  situations;  mockernut  has  nothing  to  commend 
it  over  pignut.  The  pecan  hickories  grow  faster  than  the  true  hick- 
ories, but  their  wood  is  generally  inferior.  This  inferiority  is  not 
very  great,  however,  and  the  best  bitternut  or  nutmeg  hickory  is 
superior  to  the  average  of  shagbark  or  pignut. 

There  is  reason  to  expect  that  hickory  will  soon  bring  more  ade- 
quate returns,  and  it  should  rank  among  the  important  timber  trees 
of  the  managed  woodlot.  Planting  will  in  many  cases  be  worth 
while,  and  sprout  reproduction  can  be  successfully  practiced  in  the 
case  of  pure  stands.  The  most  important  method,  however,  will  be 
the  growing  of  hickory  in  uneven- aged,  mixed  stands,  in  which  the 
reproduction  of  hickory  is  already  very  good.  Given  its  proper 
place  in  the  forest,  there  should  be  no  difficulty  in  maintaining  the 
supply  of  hickory,  and,  under  management  which  will  eliminate  infe- 
rior species  and  trees,  secure  thrifty  growth,  and  harvest  the  crop 
before  it  is  overmature,  the  quality  of  the  yield  will  be  greatly 
improved,  and  the  quantity  increased. 

The  technical  value  of  the  wood  differs  greatly  within  the  same 
species  under  similar  silvicultural  conditions,  and  even  within  an  indi- 
vidual tree.  Often  these  differences  can  not  be  accounted  for,  but 
in  general  the  wood  put  on  by  a  thrifty  tree  during  the  period  of  its 
greatest  vigor  is  the  best,  and  the  wood  from  the  butt  cuts  is  superior 
to  that  from  the  upper  cuts.  Within  the  limits  of  normal  growth  the 
width  of  the  rings  is  not  a  measure  of  the  technical  value  of  the  wood, 


64  THE   COMMERCIAL   HICKORIES. 

and  for  thrifty  trees  of  the  same  age  there  are  no  differences  in  value 
according  to  geographic  regions  or  local  soil  conditions.  Strength 
and  toughness  ace  not  affected  by  the  change  from  sapwood  to 
heartwood.  The  best  criterion  of  the  value  of  the  wood  is  its  weight. 
To  help  prevent  shortage  in  the  supply,  hickory  users  should  take 
action  to  prevent  waste  through  placing  red  hickory  upon  an  equal 
footing  with  the  white,  to  secure  economy  in  usage  through  closer 
cooperation,  and  to  improve  the  economic  position  of  the  tree 
through  the  adoption  of  a  just  log  measure. 


Bui.  80,  Forest  Service,  U.  S.  Dept.  of  Agriculture. 


PLATE  V. 


A  PLANTATION  OF  BIG  SHELLBARK  27  YEARS  OLD. 
[The  spacing  was  originally  4  by  4  feet,  but  the  stand  has  been  thinned.    Champaign  County,  111.] 


Bui.  80,  Forest  Service,  U.  S.  Dept.  of  Agriculture. 


PLATE  VI. 


FIG.  1  .—REPRODUCTION  OF  HICKORY  IN  A  FIELD  CUT  OVER  FOUR  YEARS  AGO  AND 
PASTURED  SEVERELY  BY  SHEEP,  CATTLE,  AND  HORSES. 

[Other  species  except  hickory  have  been  killed  back.  This  illustrates  strikingly  the  persistent 
sprouting  capacity  of  hickory  and  its  relative  immunity  from  browsing  by  cattle.  Defiance 
County,  Ohio.] 


FIG.  2.— A  YOUNG  STAND  OF  HICKORY  AFTER  THE  MORE  MATURE  TREES  HAVE 

BEEN  CUT. 

[This  leaves  groups  of  young  trees  to  take  the  place  of  the  old  ones,  and  is  the  right  way  to  raise 
hickory     Fulton  County,  Ohio.] 


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